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We measured the austenitic FeCr18Ni12.5 stainless steel Hugoniot as a function of crystallographic direction to approximately 60 GPa. We shock-compressed FeCr18Ni12.5 samples oriented along ⟨ 100 ⟩ , ⟨ 110 ⟩ , and ⟨ 111 ⟩ to mean stresses ranging 30.5–58.1 GPa via Ta plate impact in a large-bore powder gun and measured the free-surface velocities with laser interferometry. We unambiguously observed the largest post-shock free-surface velocity along ⟨ 100 ⟩ in each experiment, which consequently produced the lowest shock velocity along that orientation. However, the propagation of experimental uncertainties through the impedance matching scheme used to compute the shock velocity produced sufficient uncertainty overlap to preclude definitive conclusion of Hugoniot anisotropy. [ABSTRACT FROM AUTHOR]

The shot peening procedure enhances the mechanical characteristics with the transformation of compressive residual stresses which helps in the increment of operational lifespan of the product. The study comprehensively analyzed the effect of consecutive shot peening procedures up to four peening passes with the coverage increases 100% on each peening pass up to 400% on the laser powder bed fused austenitic stainless steel and compared with the as-built condition focusing on surface characteristics, mechanical characteristics, and corrosion potential. Surface damage of the peened samples was found very minimal with the absence of visible scan tracks and unmelted powder particles due to the controlled peening parameters. The inducement of compressive residual stresses (−625 MPa) was observed to be higher at the fourth consecutive peening passes without strain-induced martensite, with an increment of hardness proportion of 29.12% with a depth of 1 mm, and increment of corrosion resistance across each peening pass. [ABSTRACT FROM AUTHOR]

Underwater laser direct metal deposition (UDMD) shows great application potential in underwater high-performance repair. The susceptibility of underwater repaired components to hydrogen embrittlement (HE) is not extensively researched yet. In this study, HE in 316L stainless steel repaired by UDMD is systematically investigated and compared with in-air direct metal deposited (DMD) 316L and conventionally manufactured (CM) 316L. The experimental results show that the high cooling rates involved in UDMD contribute to a "austenite-ferrite" solidification mode. The cellular structure with a high-density of dislocations increases the tensile strength of as-built UDMD 316L. Thermal desorption spectroscopy analysis reveals that the hydrogen concentrations are similar for 316L manufactured by three processing methods, suggesting that the complex microstructural features by UDMD and DMD do not provide additional H-trapping sites. SSRT results show that the HE susceptibility is in the sequence: CM 316L (30.7%) > UDMD 316L (15.1%) > DMD 316L (9.6%). Compared with CM 316L, the stable cellular structure and higher stability towards martensitic transformation of as-built 316L are beneficial for the HE resistance. In the hydrogen-charged UDMD 316L, the hydrogen-assisted dislocation movement and mechanical twinning formation enhance the localized plasticity and induce cracking. The micron-sized oxide particles and micro-pores further contribute to the fast decohesion of interfaces in the presence of hydrogen. Those combined effects lead to the reductions in tensile strength and elongation of the hydrogen-charged UDMD 316L. • High cooling rates in UDMD lead to cellular structures with high dislocation density. • Complex microstructures in UDMD 316L do not provide additional H-trapping sites. • HE susceptibility of UDMD 316L is larger than that of in-air DMD 316L. • H-assisted dislocation movement and twinning formation induce cracking of UDMD 316L. • Micron-sized oxide particles and micro-pores with H contribute to premature failure. [ABSTRACT FROM AUTHOR]

AISI 301LN metastable austenitic stainless steels (MASSs) are known to exhibit high work‐hardening rates attributed to martensite evolution during straining which results in the second‐phase strengthening mechanism. This enhances surface hardness and potentially reduces wear and rolling contact fatigue (RCF). The aim of this study is therefore to evaluate the work hardening, wear, and RCF performance of AISI 301LN metastable austenitic stainless steel as a possible alternative material for rolling and sliding applications by varying the contact conditions such as slip ratio against the standard R350HT rail steel using a twin‐disc simulator. The results show that 301LN MASS has high surface work hardening and increased hardness because of martensitic transformation, while R350HT rail steel has only slightly changed. The formation of a hard martensitic phase is also confirmed by X‐ray diffraction analysis as well as by two other techniques, indicating a secondary hardening effect. Although it shows potential for work hardening, its susceptibility to wear‐related problems may make it less suitable for rolling and sliding applications due to a cracking and spalling mechanism induced by martensite formation. The surface strains required for the observed martensite formation are calculated and found to be very high, approaching 0.4. [ABSTRACT FROM AUTHOR]

316 Austenitic stainless steel (AusSS) is extensively utilized in high‐temperature industrial applications such as boiler tubes and nuclear reactor pressure vessels. These components commonly experience failure under high‐temperature and high‐pressure conditions, attributed to either creep or fatigue. Existing classical models for creep and fatigue life prediction focus on a singular failure mode (either creep or fatigue) and consider physical features only. This study aims to develop a unified life prediction model for both creep and fatigue phenomena. It synthesizes information from 12 additional unexplored chemical and microstructural features from the National Institute of Materials Science (NIMS), Japan database, and previously published literature. Machine learning (such as decision tree, random forest, and XGBoost) and deep learning (like deep neural network) algorithms are employed in the modeling process. The trained models have been cross‐validated against unseen creep and fatigue life data, demonstrating superior prediction accuracy of 96.1% for deep neural network compared with classical models. Highlights: Unified prediction model for both creep and fatigue life prediction.Investigated the effect of up to 20 physical, chemical, and microstructural features.Multiple ML and DL prediction models were developed and compared with classical ones. [ABSTRACT FROM AUTHOR]

Wire arc additive manufacturing (WAAM), based on gas metal arc welding, is ideal for fabricating components with sizeable geometries and moderate structural intricacies. However, the electric arc introduces a heat source and directional heat dissipation during deposition, resulting in undesired microstructural characteristics, such as columnar dendritic structures, which lead to variations in hardness across the printed component. Our previous research introduced the friction stir burnishing (FSB) tool integrated with WAAM using a hybrid approach called simultaneous processing. This method suppressed dendrite formation and enhanced the microstructure within WAAM. This approach directly correlates process dynamics, force dynamics, and temperature control, facilitating efficient plastic deformation. This research investigates the relationship between process parameters and microhardness within the combined manufacturing systems of WAAM and FSB tools. The study primarily focuses on using SUS 316L austenitic stainless steel wire material for WAAM and examines how simultaneous operation with the FSB tool impacts microstructure and microhardness. The investigation emphasizes three key parameters: the distance between the welding torch and the FSB tool, tool rotational speed, and machine feed speed. Comprehensive experimentation, including Taguchi analysis, determines optimal values for these parameters. Results indicate that torch-to-tool distance and machine feed speed significantly influence microhardness, while tool rotational speed shows minimal impact. The most effective combination for enhancing microhardness was a torch-to-tool distance of 20 mm, a machine feed speed of 528 mm/min, and a tool rotational speed of 1900 rpm. This combination induced a plastic deformation transformation effect, contributing to the overall improvement in microhardness. Additionally, the optimal parameters for achieving a smaller grain size were a torch-to-tool distance of 17 mm, a machine feed speed of 356 mm/min, and a tool rotational speed of 1900 rpm, as indicated by the average grain size. Furthermore, this study shows significant improvements in microstructure and hardness within 50–200 µm depth from the surface. Comparative analysis between FSB tool-processed and non-processed samples indicates a 22.51% increase in microhardness, with the grain size of the simultaneous process being 7 µm compared to 11.55 µm. Optimizing the process parameters of simultaneous processing achieves superior microhardness and microstructural refinement. Additionally, it highlights the need for further material development to address challenges associated with tool durability, paving the way for advancements in simultaneous processes. [ABSTRACT FROM AUTHOR]

In this paper, a review of the analysis of Fe 2p3/2 peak and other transition metals in the austenitic stainless steel literature is presented. It reveals the significant shortcomings of the most widely used approaches, based on the principle of "chemistry fitting," where single symmetric peaks are used to represent either individual oxidation states or specific compounds. No meaningful conclusions can be drawn from these commonly employed two- or three-component peak fitting (2C and 3C) approaches; the implication being that a large portion of the literature that relies on this approach is flawed. As a significantly more accurate and reliable alternative to "chemistry fitting," we also assess "envelope fitting" (using empirical multiplet structures) and examine its limitations when applying the approach to austenitic stainless steel data. A detailed comparison of these two fitting approaches is described in Part I. For other elements such as Cr 2p, the problems associated with using single components to represent oxidation states or compounds are not as severe. It was found that it does not impact binding energy measurements, but does influence relative intensities, which will have a flow-on effect for oxide thickness calculations and obtaining a correct understanding of the surface more broadly. [ABSTRACT FROM AUTHOR]

A total of 316 austenitic stainless steel (ASS) coatings were deposited on 22MnB5 press-hardening steel plates by varying the substrate bias voltages using a magnetron sputtering technique and quenched in a flat mold with cooling water. The substrate bias current and ion-bombardment energy densities increased up to 0.5 mA/mm2 and 50 J/mm2 at a high voltage of −100 V, and, therefore, the variations in the coatings' morphologies were owing to the increases in the ion bombardment. The porous bulk pattern appeared in the quenched ASS coating at −100 V, clearly different from the porous columnar structure of the others at −50 and −75 V. The γ-Fe and α-Fe phases were observed from the diffraction peaks, presented the ASS coating and 22MnB5 substrate, respectively. There was no intermetallic compound (IMC) peak detected. In addition, the diffusion layer of the quenched ASS-coated plate was observed, in which its morphology was different from the quenched martensite (M) plate, and proved to be the α-Fe microstructure by the very low α-Fe peak at the standard (110) position. The bright image of TEM and the select area electron diffraction pattern indicated the nanostructure of the quenched ASS coating. The nanohardness of the ASS coating, diffusion layer, and M plate (7.36, 3.60, and 6.25 GPa, respectively) was detected, indirectly proving an α-Fe structure of the diffusion layer. The fracture angles of the 316-coated plates significantly improved from 51.82° at −50 V, 53.77° at −75 V to 57.38° at −100 V, as the ASS structure changed to be porous bulk pattern. The clearance of IMC, coating's porous bulk pattern, and the low hardness α-Fe diffusion layer benefited for the fracture strain by lengthening the pathway of the crack's development and blocking the further crack's propagation, respectively. [ABSTRACT FROM AUTHOR]

Solid-to-solid diffusion bond between ferritic SA508 low alloy steel (LAS) and austenitic 316L stainless steel (SS) via hot isostatic pressing (HIP) was evaluated. This study investigated the microstructural and mechanical evolutions of the bimetallic interface before and after heat treatment. The interfacial region between two materials demonstrated uniform microstructure, no visible manufacturing defects, and higher interfacial hardness and tensile strength. The joint interface was stronger than for both 316L SS and SA508 LAS. The interfacial hardening was attributed to the significant grain refinement at the interface region and dislocation hardening under as-HIP'ed condition. Post-HIP heat treatment considerably reduced the interfacial strength, attributed to dislocation recovery and grain growth. From the mechanical perspective, the work confirmed utilizing HIP capsules during HIP manufacturing provides adequate interfacial strength between 316L SS HIP capsule and SA508 LAS for cladding purposes. The 316L SS HIP capsule may be used as the cladding layer for corrosion protection. [ABSTRACT FROM AUTHOR]

This study investigates the relationship between grain size and material parameters defined in the microscopic hardening laws of the phenomenological crystal plasticity model of Méric–Cailletaud. This investigation is essential for accurate cyclic loading simulations, where the grain size effect on kinematic hardening cannot be neglected. The work was carried out through finite element simulations of the macroscopic plastic behavior of six representative volume elements (RVEs), of austenitic stainless steel 316L, varying in grain size, using a model of Méric–Cailletaud, implemented within the Abaqus software. Experimental literature results serve as benchmarks for adjusting grain size-related hardening parameters. The findings reveal that the studied parameters obey the Hall–Petch law and exhibit an inverse relationship with the square root of the grain size. What is noteworthy is the effect of grain size on kinematic hardening, which differs significantly from previous studies where kinematic hardening parameters were kept constant. Additionally, parameter evolution varies notably between microstructures with coarse and fine grains. Finally, determining hardening parameter variation as a function of grain size provides us with an extended model of Méric–Cailletaud capable of predicting the local as well as the global mechanical behavior of stainless steel 316L in both monotonic and cyclic loading cases, considering the grain size effect. [ABSTRACT FROM AUTHOR]

Interrupted and incremental tensile tests have been carried out on 316 austenitic stainless steel at different strain rates, revealing the correlation between the strain, strain rate, and temperature rise of martensitic transformation. The FERITSCOPE FMP ferrite tester and Telops FAST M2K infrared imager measured the martensite content and surface temperature rise at different strain rates, respectively. The effect of adiabatic temperature rise and strain rate on martensitic transformation was isolated by incremental tests. Compared with the incremental tensile test at a low strain rate (0.001 s−1), it has been found that the increase in strain rate has a negative effect on martensitic transformation, and the effect of strain rate on martensitic transformation seems to be more significant than that of adiabatic temperature rise. The formation and evolution mechanism of strain-induced martensitic transformation of 316 austenitic stainless steel were studied by electron backscattered diffraction. During the process of tensile plastic deformation, the nucleation and growth of new martensite mainly occurred near the twin boundary. [ABSTRACT FROM AUTHOR]

In this work, the oxidation properties of austenitic 316L stainless steel powder and sintered porous support were investigated at the temperature range of ~600-750 䨽 for 100 hours in ambient air. Oxidation kinetics was determined by continuous thermogravimetry and analyzed employing parabolic rate law. It was observed that oxidation leads to the formation of an oxide scale, with substantial oxidation occurring at = 650 ℃ in the powder. The porous steel support was fabricated using the tape casting method with two distinct pore former concentrations. The microstructural features of both the powder and support were investigated by X-ray diffractometry and scanning electron microscopy coupled with energy-dispersive X-ray analysis. The mechanical properties of the metal support were examined before and after oxidation via a microhardness test. The effect of porosity on the resulting properties of the metal support was also highlighted. In summary, 316L stainless steel support suits SOCs applications below 600 ℃. [ABSTRACT FROM AUTHOR]

Tailor weld blank (TWB) is preferred in different components of automobiles to reduce weight of the vehicle. However, TWBs have lower formability than sheets because of increased hardness and strength of weld region. Hence, in this work, detailed formability analysis of TWB of AISI304 is done and compared with as-received sheets along with microstructural correlation. Forming limit diagram for as-received sheet, TWBs are determined. Strain hardening exponent value of as-received sheet is 0.381, unweld region and weld region of TWB is observed to be 0.362 and 0.301, respectively. Numerical simulations were also done for predicting the FLC of TWB of AISI304 with the help of PAM STAMP 2 G solver. TWB showed lower formability than as-received sheets. Similarly, predicted FLD for TWB is almost coinciding with the experimental value. Similarly, optical micro-structure studies were also analysed for as-received sheet, unweld region and weld region of TWB, which showed fully austenitic structure with random grain orientations. At the same time, it was found that strain path chosen for FLD determination has a strong influence on microstructure evolution. [ABSTRACT FROM AUTHOR]

Understanding the impact of high-temperature thermal cycle on coating composition and its corrosion characteristics is essential for coating development. The present study investigated NiCr/TiO2-coated 316L austenitic stainless steel (316L SS) under thermal shock exposure and their corrosion behaviour in 3.5% NaCl solution. The electrochemical parameters were evaluated using potentiodynamic polarisation and electrochemical impedance spectroscopy techniques to understand the corrosion characteristics. Various techniques, viz. field emission scanning electron microscope, energy-dispersive X-ray spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy, were employed to examine the morphology, elemental composition, crystalline and oxidation characteristics of all the samples. The NiCr/TiO2-coated 316L SS demonstrated thermal resistance up to 9-h oxidation period and five thermal cycles. Afterwards, with gradual weight loss, TiO2 spallation appeared on the coated samples. The as-deposited sample revealed an increased pitting potential of 118.76% and improved corrosion resistance over ten times in magnitude than the bare sample. This improvement in the coated sample is attributed to high charge transfer resistance and chemically stable coating layer between the metal matrix and corrosive solution. In contrast, the delaminated sample revealed over four times greater resistance than the bare sample, which is credited to the limited surface area for possible redox reactions and passive NiCr bond coat layer over the metal matrix. [ABSTRACT FROM AUTHOR]

A three‐dimensional (3D) microstructural volume is reconstructed from a stack of two‐dimensional sections which was obtained by serial sectioning coupled with electron back scattering diffraction (EBSD) mapping of a 316L austenitic stainless steel. A new alignment algorithm named linear translation by minimising the indicator (LTMI) is proposed to reduce the translational misalignments between adjacent sections by referencing to coherent twin boundaries which are flat and lying on {111} planes. The angular difference between the measured orientation of a flat twin boundary and that of the {111} plane is used as an indicator of the accuracy of the alignment operations. This indicator is minimised through linear translations of the centroids of triangular facets, which constitute grain boundaries at a distance not restricted by the in‐plane step size of the EBSD maps. And hence the systematic trend in the translational misalignments can be effectively reduced. The LTMI alignment procedure proposed herein effectively corrects the misalignments remained by other methods on a 3D‐EBSD data prepared using serial sectioning methods. The accuracy in distinguishing between coherent and incoherent twin boundaries is significantly improved. [ABSTRACT FROM AUTHOR]

This work aims to evaluate the behavior of AISI 308L stainless steel, applied in additive manufacturing by direct energy deposition (DED) with the GTA (TIG) process, to find the limits of using this material as a manufacturing technique. The AISI 308L is an austenitic steel with extensive applications across various industrial sectors, particularly in the chemical, food, and biomedical industries. Due to its resistance to ductile–brittle transition, it is widely utilized in cryogenic temperature working conditions. The welding equipment and the test specimen were instrumented for analysis of welding process parameters and evaluation of heat transfer in the material as a function of pulse frequency (0 Hz—conventional GTA, 100 Hz, 1 kHz, and 10 kHz) to determine its influence on ferrite morphology and printability in each test specimen. Under these conditions, the sample was characterized by optical and scanning electron microscopy (SEM) and backscattered electron diffraction (EBSD) to evaluate the direction of solidification by the deposited layer. The results showed that a pulse frequency of 100 Hz reduced the volumetric fraction of ferrite and exhibited the best printability. Furthermore, samples prepared using the pulse frequency showed higher printability values than samples without pulsation, and samples with 10 kHz showed an increase in the formation of acicular ferrite. [ABSTRACT FROM AUTHOR]

Controversy surrounds the potential of grain refinement in suppressing metal hydrogen embrittlement (HE). The literature presents two methods for introducing hydrogen into metals: hydrogen pre-charging (HPC) and hydrogen in-situ charging (HISC). This study compares the effect of grain refinement on HE under electrochemical HPC and HISC conditions, focusing on type 304 austenitic stainless steel with a grain size range of 0.5–35 μm. HE behaviors were evaluated through tensile testing and fracture morphology analyses, while hydrogen diffusion and concentration were examined using hydrogen uptake amount measurements and hydrogen permeation tests, complemented by finite element (FE) simulations. Results indicate that coupling with plastic deformation significantly accelerated hydrogen transport in the HISC condition, leading to higher apparent hydrogen diffusivity compared to the HPC condition, with grain boundaries (GBs) act as hydrogen traps. Under the HISC, grain refinement reduced HE susceptibility by decreasing the apparent diffusivity due to an increased trapping effect of GBs and suppressing intergranular fracture by reducing the hydrogen amount distributed to each GB (hydrogen occupancy of the GBs). However, grain refinement to below 1 μm increased HE under the HPC condition. Hydrogen permeation tests showed that under the HPC, grain refinement slightly decreased hydrogen diffusivity. In the ultrafine-grained specimen, as GBs trapped more hydrogen atoms, they not only provided hydrogen to stress-concentrated lattices and newly-formed dislocations by detrapping but also maintained a higher hydrogen occupancy of the GBs, thus increasing HE. It is concluded that whether grain refinement suppresses HE depends primarily on the resulting hydrogen occupancy of the GBs, which is influenced by the charging conditions rather than the quantity of traps. • A comparison of effect of grain size on HE in 304 steel is conducted under in-situ H charging and pre-charging. • Coupling with plastic deformation accelerates H transport in in-situ charging condition. • Grain refinement reduces HE in in-situ charging, but it slightly decreases and then increases HE in pre-charging. • The former is attributed to decreased H diffusivity and reduced H occupancy of grain boundaries (GBs). • The latter is due to that H-filled GBs act as H reservoirs, providing H to stress concentrations and dislocations. [ABSTRACT FROM AUTHOR]

The wear and corrosion resistance of 316L austenitic stainless steel after strain hardening were studied. 316L austenitic stainless steel was composed of a large amount of austenite and a small fraction of martensite. After strain hardening at room temperature, the contents of phases were not changed basically. With the increase of pre-strain deformation, the microhardness of the surface and cross-section slightly increased, and the microhardness of the sample with pre-strain deformation of 20% was the largest. When the pre-strain deformation was greater than 5%, the surface microhardness was greater than the cross-sectional microhardness. The dynamic average friction coefficients of the stainless steel after pre-strain deformation of 0%, 5%, 10%, and 20% were 0.67, 0.57, 0.2, and 0.12, respectively. The friction coefficient of the samples gradually decreased with the increase of strain hardening. The wear resistance of 316L stainless steel was improved after pre-strain deformation. The steel with pre-strain deformation of 20% had a small abrasive scratch depth and low friction coefficient, which exhibited good wear resistance. The corrosion resistance of the samples after strain hardening deteriorated for the initial state without immersion due to the existence of defects. The corrosion resistance of the sample with pre-strain deformation of 5% after soaking for 3 days was the best, compared with the other as-strained samples. [ABSTRACT FROM AUTHOR]

In this study, pure iron, S45C carbon steel (Fe–0.45mass%C), carburized iron, and nitrided iron are bonded with two types of stainless steels, i.e., SUS304 austenitic stainless steel (Fe–18mass%Cr–8mass%Ni) with face center cubic structure or SUS430 ferritic stainless steel (Fe–18mass%Cr) with body center cubic structure by a spark plasma sintering (SPS) machine. Bonding experiments are carried out by SPS bonding. It is found that the bonding temperature of the S45C/SUS samples is lower than that of Fe/SUS samples, and carbon atoms in the S45C play important role on the bonding performance. The bonding temperature for SUS304/SUS430 sample is more than 30 °C higher than those for the Fe/SUS and S45C/SUS samples. The presence of thin chromium oxides on both stainless steels reduces the bonding performance of SUS304/SUS430 sample. Better bonding performance is found for the carburized and nitrided iron for bonding with stainless steels. However, continuous single‐phase layer on the surface leads to reduce the bonding performance. It is concluded that not only the concentration of carbon and nitrogen but also the phase configuration in the iron at interface strongly influences the bonding performance between iron alloys and stainless steels by SPS bonding. [ABSTRACT FROM AUTHOR]

Ferritic/martensitic steels and austenitic stainless steels are high‐strength steels, and highly recommended in high‐temperature and high‐pressure application. In general, multimetallics with different Inconel alloys are used for joining. This is quite a complex and time‐consuming procedure. The current work demonstrates the efforts made to weld 8 mm‐thick P91 steel and 316L SS plates in a single pass using activating flux tungsten inert gas (A‐TIG) welding process without any interlayers. The main challenge is to get the symmetric weld bead profile. Flux coating is optimized in terms of flux composition, coating density, and coating pattern to get the full penetration with symmetric appearance. The current work discusses the possible cause and their solution of asymmetricity during dissimilar welding. Differential flux coating density is found to be very effective in controlling the arc column shape, fluid flow, and consequently the bead geometry. High coating density is used in the P91 side compared to 316L side. Symmetric weld profile with full penetration is achieved by applying multicomponent flux (33–38% TiO2, 38–43% SiO2, 13–17% NiO, and 8–10% CuO) during A‐TIG welding. [ABSTRACT FROM AUTHOR]

This study explores the impact of microstructural features on fatigue crack initiation in poly‐crystalline materials, emphasizing hydrogen‐induced complexities. Grain anisotropy, misorientations, grain size variations, and elastic–plastic inhomogeneities concentrate stress at grain boundaries, making them susceptible to crack initiation during fatigue loading. The presence of hydrogen compounds this process, due to complications of characterization of local hydrogen content and activating embrittling mechanisms. Building upon a model for nickel, this research investigates 316L austenitic stainless steel specimens with varying grain sizes, both uncharged and hydrogen‐charged. In situ low‐cycle fatigue loading experiments establish correlations between fatigue crack initiation and microstructural features. The study reveals specific combinations of features crucial in the initiation process, undergoing alterations in the presence of hydrogen. A proposed qualitative model links microstructural features with accumulated plastic shear strain during fatigue and prevalent hydrogen embrittlement mechanisms like hydrogen‐enhanced local plasticity and hydrogen‐enhanced decohesion. [ABSTRACT FROM AUTHOR]

Digital image correlation (DIC) technology can capture strain anomalies and predict crack initiation providing early warning of material failure. Herein, DIC technique is used to calculate the full‐field strain by analyzing the grayscale patterns of speckle images during the tensile process. This allowed for an analysis of the microstructure evolution of the 316LN austenitic stainless steel (SS) at cryogenic temperatures. Deformation behavior of the 316LN SS at cryogenic temperatures is further analyzed using electron backscatter diffraction technology and transmission electron microscopy. Based on the strain field obtained by the DIC technique, a comprehensive analysis of the martensite volume fraction at different strains can be conducted. The results show that the strain localization under cryogenic deformation is related to martensitic transformation, while the random distribution of slip bands aligns with local strain peak values. Notably, fracture under cryogenic deformation occurs in regions where the strain field reaches its peak, rather than at locations with the maximum strain value. [ABSTRACT FROM AUTHOR]

The root cause failure investigation for a ruptured secondary superheater (SSH) tube in a heavy oil-fired boiler was undertaken. The technical investigation disclosed severe microstructural degradation in terms of intermetallic phase precipitation, creep cavities and carburization of tube's external surface. The dimensional survey revealed significant thickness reduction along periphery of fractured surface. A semi-quantitative analysis of surface deposits was performed by scanning electron microscopy and x-ray diffraction to characterize and identify the sources of corrosive deposits. The detection of low melting eutectic vandates in external deposits induced the possibility of fireside corrosion. A comparative analysis was drawn between competing mechanisms of fireside corrosion and long-term overheating to reckon the root cause of the failure. Furthermore, a microstructural evolution model for fine-grained austenitic stainless steel (SA-213 TP347 HFG) suffering simultaneously from fireside corrosion and long-term overheating was developed. The investigation was concluded with notable recommendations and protective measures against fireside corrosion for superheater tubes for boiler life extension and maintaining overall equipment reliability. [ABSTRACT FROM AUTHOR]

This paper investigates the leak failure of an austenitic stainless steel condenser tube observed during the hydrostatic test operation using visual inspection, scale analysis, and the micrographic analysis by scanning electron microscope equipped with energy-dispersive X-ray spectroscopy (SEM/EDS). The results showed that the inner surface of the failed condenser tube experienced the localized pitting corrosion, initiated from the inner, and continued through the thickness of the tube. Rod-like and leaf stalk-like microorganisms and the biofilm were found in the scale layer covering the affected area. Tunneling corrosion attack was also clearly found. EDS spectra results indicated the significant sulfur content in corrosion pits. All of the findings indicate that microbiological-influenced corrosion assisted by sulfate reduction bacteria was response for the leakage failure of the condenser tube. [ABSTRACT FROM AUTHOR]

The study investigates the impact of mechanical cleaning, citric acid+sodium hydroxide (CA), and nitric acid (NA) passivation on welded SS304 stainless steel plates, taking into consideration surface roughness. An innovative EIS paste–based cell is employed for this purpose. Welded systems in both the heat-affected (HAZ) zone and base metal (BM) are being analyzed before and after each treatment. Specifically, one welded plate underwent mechanical cleaning, another was solely subjected to CA passivation, and a third received both mechanical cleaning and CA passivation. Aging tests were conducted in a condensation chamber to confirm the effectiveness of cleaning and passivation treatments. Regarding open-circuit potential (OCP), most samples remained within the passive region, except for the mechanically cleaned heat-affected zone and the intentionally abraded surface immediately after abrasion. Rp values, which are in line with the OCP measurements, range from 104 to 107 Ω cm2 for all the observed samples. As the degree of abrasion on the NA-passivated surface increases, the electrochemical impedance spectroscopy (EIS) spectrum shifts from that characteristic of the passive towards that characteristic of the active state of the stainless steel. [ABSTRACT FROM AUTHOR]

This study investigated the role of interfacial deformability in bond integrity and strength, particularly in the production of robust joints between harder austenitic stainless steels (SS) during ultrasonic welding. The specimen without the interlayer experienced limited strength enhancement owing to internal cracking from continuous sliding at interfacial temperatures below 0.6 times the melting point (Tm), which is attributed to the limited deformability of the austenitic SS. In contrast, introducing Fe and Ni interlayers between the substrates resulted in a notable increase in the interfacial strength, surpassing 2500 N in the peak load within a reduced welding duration. The correlation between the interfacial strength and the peak temperature suggests that a substantial decrease in hardness below 0.4 Tm is sufficient for extensive bond formation. Moreover, dynamic recrystallization (DRX) led to grain refinement in the Fe interlayer owing to shorter weld durations, whereas grain growth was observed in the Ni interlayer due to higher peak temperatures. Both the Fe and Ni interlayers significantly improved the bonding integrity by accommodating plasticity through the above phenomena without severe damage to the substrates, leading to increase of interfacial strength by 24% (2050 N to 2500 N) and reduction of weld duration by 40% (1.5 s in Fe interlayer). In addition, the fracture position after the lap shear test shifted from the edge of the weld area to the SS substrate. [ABSTRACT FROM AUTHOR]

304 austenitic stainless-steel (SS) strip-based carbon fiber metal laminates (CFMLs) have raised significant concerns, in terms of their mechanical performance. On top of that, the hybrid laminates' interlamination performance is vital in regulating their failure patterns. Along these lines, in this work, SS strips with regulatable micromorphology and composition were obtained by using physical and chemical surface modification strategies, including polishing, acid etching, anodization, and thermal treatment. The shear strength of the treated-SS/epoxy single lap joints (two treated-SS strips bonded by the epoxy resin via hot curing process) was systematically explored, and the origins of the enhancement mechanism were attributed to the resulting surface microstructure, as well as the possible chemical reactions between the treated surface and the curing agent. The etching-anodizing-thermally treated-SS (EAT-SS)/epoxy joint exhibited the maximum shear strength (16.04 MPa) and work of fracture (5.85 kJ·m−2) due to the substantial cohesive failure pattern of the epoxy. The encouraging enhancement was mainly attributed to the synergistic effect of the micro-annular pit and the nanoporous array structure of the EAT-SS surface. These effects induced a significant mechanical interlock and a plausible chemical reaction at the interface, which led to improved bonding strength between the epoxy and treated-SS surface. Overall, in this work, it was demonstrated that the combination of the anodization and thermal treatment can effectively improve the interlamination bonding properties between the SS strip and the epoxy resin due to the combination effect of mechanical interlocking and chemical bonding. [ABSTRACT FROM AUTHOR]

Dissimilar welds between ferritic and austenitic stainless steels are widely used in industrial applications. Taking into account the issues inherent to arc welding, such as the high heat input and the need to carry out multiple passes in the case of thick plates, a procedure with two simultaneous laser beams (working in a single pass) and consumable inserts as filler metal has been considered. Particular attention was paid to the choice of the filler metal (composition and amount), as well as welding parameters, which are crucial to obtain the right dilution necessary for a correct chemical composition in the weld zone. The first experimental investigations confirmed the achievement of a good weldability of the dissimilar pair ASTM A387 ferritic/AISI 304L austenitic steel, having ascertained that the microstructure of the weld zone is austenitic with a little amount of residual primary ferrite, which is the best condition to minimize the risk of hot cracking. [ABSTRACT FROM AUTHOR]

This paper reports experimental results concerning the corrosion of 316L austenitic stainless steels produced by ball milling and spark plasma sintering in NaCl electrolyte. Specimens with grain sizes ranging from 0.3 µm to 3 µm, without crystallographic texture, were obtained and compared with a cast that is 110 µm in grain size and an annealed reference. The potentiodynamic experiments showed that the reduction in grain size leads to a degradation of the electrochemical passivation behavior. This detrimental effect can be overcome by appropriate passivation in a HNO3 concentrated solution before consolidation. The Mott–Schottky measurements showed that the semiconducting properties of the passive layer do not vary significantly on the grain size, especially the donor density, which is responsible for the chemical passivation breakdown by chloride anions. The total electrical resistance of the layer, measured by impedance spectroscopy is always lower than the one of a cast and annealed 316L, but it slightly increases with a reduction in grain size in the ultrafine grain range. This is followed by a slight increase in the thickness of the oxide layer. The effect of chloride ions is very pronounced in terms of passivation breakdown if the powder is not passivated prior to sintering. This leads to the nucleation and growth of subsurface main pits and the formation of secondary satellite pits, especially for the smallest grain sizes. Passivation of the 316L powder before sintering has been found to be an effective way to prevent this phenomenon. [ABSTRACT FROM AUTHOR]

Effects of Nb on the creep resistance and hot corrosion behavior of the Fe-25Cr-35Ni-2.5Al-xNb (x = 0, 0.6, 1.2) Alumina-Forming Austenitic stainless steels (AFA steels) at 700 °C were investigated. The addition of Nb promoted the precipitation of both nanoscale NbC and γ′-Ni3(Al, Nb) phases, which exhibited very low coarsening rate constants. The nanoscale NbC and γ′-Ni3(Al, Nb) phases effectively impeded the migration of dislocations and led to an improvement in creep performance of the Nb-addition AFA steel. The corrosion of AFA steels in Na2SO4-25%K2SO4 at 700 °C was primarily driven by an "oxidation-sulfidation" mechanism. The addition of Nb, serving as a third element, facilitated the formation of protective Cr2O3 and Al2O3 films, which improved the hot corrosion resistance performance. However, the formation Nb2O5 was found to compromise the compactness of the oxide film, which adversely affected the corrosion resistance. [ABSTRACT FROM AUTHOR]

Austenitic stainless steel (ASS) and duplex stainless steel (DSS) are referred as "difficult-to-cut" materials in the manufacturing industry because of different machining difficulties including work hardening, high cutting temperatures and formation of built-up layers. DSS is the preferred replacement for ASS but includes a difficult manufacturing environment. Moreover, the wet machining conditions raise several issues related to the human health, environment, disposition and costing. However, turning of these materials in the dry environment is a challenging task. The present research work is a comparison of machinability aspects of ASS 304 and DSS 2205 in a dry environment using AlTiN coating deposited by two advanced coating deposition techniques including direct current magnetron sputtering (DCMS) and high-power impulse magnetron sputtering (HiPIMS). Uncoated tools showed the worst performance at every stage of machining. AlTiN (HiPIMS)-coated tools showed the lowest increase in average surface roughness of 8%, 17% lower cutting force and 1.5-times higher tool life compared to AlTiN (DCMS) tools. DSS 2205 was the most difficult material to machine in dry conditions, exhibiting the lowest average tool life of 3890 mm compared to 4315 mm by ASS 304. Moreover, HiPIMS-coated tools helped in improving the machining performance of DSS 2205 up to some extent. [ABSTRACT FROM AUTHOR]

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Selective laser melting (SLM) is a rapidly evolving technology that requires extensive knowledge and management for broader industrial adoption due to the complexity of phenomena involved. The selection of parameters and numerical analysis for the SLM process are both costly and time-consuming. In this paper, a three-dimensional radial basis function-finite difference (RBF-FD) meshless model is introduced to accurately and efficiently simulate the molten pool size and temperature distribution during the SLM process for austenitic stainless steel (AISI 316L). Two different volumetric moving heat source models were presented, namely the ray-tracing method heat source model and the double-ellipsoidal shape heat source model. The temperature-dependent material properties and phase change process were also considered, based on experiments and effective models. Results of the model for the molten pool size were validated with those of the literature. The proposed approach can be used to predict the effect of different laser power and scan speed on the molten pool size and temperature gradient along the depth direction. The result reveals that the depth of the molten pool is more sensitive to laser power than scan speed. Under the same scan speed, a 22% change in laser power (45 ± 10 W) affects the maximum temperature proportionally by about 9%. The developed algorithm is computationally efficient and suitable for industrial applications. [ABSTRACT FROM AUTHOR]

The autogenous manual gas tungsten arc welding (GTAW) process was used for cladding austenitic stainless steel 316L using a single pass with various contact tip-to-work distances (CTWDs). Immersion and electrochemical tests were used to evaluate the corrosion resistance of the welded specimens, and a microstructural analysis was conducted to investigate the chemical composition of the molten pool and the heat-affected zone of welding. The key findings of this study indicate that the corrosion resistance improved under a CTWD of 5 mm due to the optimal distribution of ferrite and a refined microstructure. Additionally, the highest hardness was observed in specimens with a CTWD of 3 mm, attributed to the increased ferrite content in the weld metal. As the CTWD increased, the ferrite fraction decreased, and the hardness also diminished. However, in the CTWD 7 mm case, the higher heat input influenced the microstructure and molten pool shape significantly through the Marangoni effect, resulting in a lower corrosion resistance. These results suggest that optimizing the CTWD can enhance the corrosion resistance of welded 316L stainless steel. [ABSTRACT FROM AUTHOR]

The machined surface residual stress plays a critical role in stress corrosion cracking resistance and fatigue performance of austenitic stainless steels. Controlling the residual stress by changing machining parameters is an effective way to improve the service performance of components. This paper explores the effects of processing parameters and tool geometric parameters on residual stress by establishing an analytical model for residual stress evaluation on machined surface. Considering the thermo-mechanical coupling effects of machining, a multi-physics framework of orthogonal cutting process is built up. From the coupling mechanical and thermal loads, the variations of stress, strain and temperature are modelled by an elastoplastic procedure. Based on the mechanism of residual stress and the loading-unloading model, the prediction of residual stress is achieved. Experimental tests are conducted for model validation. By simulating the cutting processes under different conditions and analyzing the main factors that affecting the stress/strain and temperature fields, the effects of cutting parameters and tool geometric parameters on residual stress are revealed. [ABSTRACT FROM AUTHOR]

This study employs neutron diffraction to investigate the relationship between residual stress and coating thickness in cold sprayed 304L austenitic stainless steel. Results show that shot peening predominantly impacts the residual stress profile, leading to substantial in-plane compressive force. The impact of laser heating, a widely used method to alter cold spray's microstructural properties, on the coating's residual stress is also analyzed. The findings indicate that the maximum compressive residual stress in the in-plane component is mainly independent of coating thickness, which suggests that the material properties determine the maximum residual stress. The cold sprayed deposits possessed compressive, nearly biaxial strain and stresses. After laser heating, these stresses were replaced by tensile residual stresses. Two analytical models, the Tsui and Clyne and the Boruah models, for predicting residual stresses are also evaluated, and both models provide reasonable fits to the experimental data. At this point, the deviations between the experimental results and the models are principally caused by the inability of the current models to address plastic deformation and relaxation, and the residual stresses generated by thermal gradients. [ABSTRACT FROM AUTHOR]

By combining the formability of injection-molded polymers with a wide range of metal options, metal injection molding (MIM) allows for manufacturing metallic components with small dimensions and complex geometries. However, steels produced through this process often exhibit higher porosity compared to conventional methods. This article aims to fill this gap by developing a thermochemical oxynitrocarburizing treatment cycle applied to the austenitic stainless steel Catamold 316L. The developed treatment analyzes the diffusion kinetics, mechanical properties, and metallurgical behavior. The oxynitrocarburizing treatment was carried out at a temperature of 570 °C for varying durations of 30, 60, and 120 min. The findings showed that surface microhardness significantly increased, and corrosion resistance improved due to the ceramic behavior of the Epsolon composite and the formation of magnetite, compared to the sintered material. The study reveals a substantial rise in residual compressive stresses of up to − 2790 MPa on the sample surface. The residual stress values and the elevated surface microhardness are highly beneficial for improving the tribological properties of Catamold 316L steel produced by the MIM process. The study suggests that using ionic oxynitrocarburizing in salt baths presents an alternative to plasma processes for treating Catamold 316L steel, providing improved diffusion of nitrogen and carbon. [ABSTRACT FROM AUTHOR]

In this work, 2D simulations of stainless steel nitriding through a mask were performed with two configurations: with and without lateral adsorption under the mask, depending on the strength of the mask adhesion. The stress-induced diffusion and trapping–detrapping process are included as the main mechanisms of nitrogen mass transport. The main focus is on the analysis of the swelling process, which affects the expansion of the material. The surface concentration profiles and topographical profiles along the surface are calculated and compared with experimentally registered ones taken from the literature, and they show a good agreement. This allows for estimation of the values of model parameters. Because nitriding processes takes place in vertical and horizontal directions, the anisotropic aspect of nitriding are analyzed. It is shown that the adherence of the mask significantly influences the topographical profile and the anisotropy of nitriding, because in the case of a weakly adhered mask, a lateral adsorption process takes place under the mask. The influence of swelling and anisotropy in the case of pattern nitriding in small dimensions is discussed. [ABSTRACT FROM AUTHOR]

The lap welding process for 304L stainless steel welded using the pulsed gas tungsten arc welding (P-GTAW) procedure was studied, and the effects of the pulse welding parameters (the peak current, background current, duty cycle, pulse frequency, and welding speed) on the macroscopic morphology, microstructure, and mechanical properties of the resultant lap joints were investigated. Tensile tests, hardness measurements, and SEM/EDS/XRD analyses were conducted to reveal the characterization of the joint. The relationships between the welding parameters; certain joint characteristic dimensions (the weld width, D; the weld width on the lower plate, La; the weld depth on the lower plate, P; and the minimum fusion radius, R); and the maximum tensile bearing capacity were studied. The weld zone was primarily composed of vermicular ferrite, skeletal ferrite, and austenite, and no obvious welding defects, precipitation, or phase transformations were evident in the weld. Microhardness tests demonstrated that the weld microhardness was highest in the base metal zone and lowest in the weld zone. As the heat input increased, the average microhardness decreased. The hardness difference reached 17.6 Hv10 due to the uneven grain size and the transformation of the structure to ferrite in the weld. The fracture location in welded joints varied as the heat input changed. In some parameter combinations, the weld tensile strength was significantly higher than that of the base material, with fractures occurring in the weld. Scanning electron microscopy results exhibited an obvious dimple morphology, which is a typical form of ductile fracture. XRD revealed no significant phase changes in the weld zone, with a higher intensity of the austenite diffraction peaks compared to the ferrite diffraction peaks. [ABSTRACT FROM AUTHOR]

Copyright of Atomic Energy Science & Technology is the property of Editorial Board of Atomic Energy Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Atomic Energy Science & Technology is the property of Editorial Board of Atomic Energy Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Atomic Energy Science & Technology is the property of Editorial Board of Atomic Energy Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the present study, effect of ultrasonic impact treatment (UIT) on the microstructural characterization and mechanical properties of 316L stainless steel (hereinafter referred to as 316L) was investigated experimentally. The fatigue fracture mechanism of 316L before and after UIT was revealed. The experimental results indicated that the martensitic grain size induced at the impact edge was about 2.00 Å. The surface modified 316L formed a gradient nanostructure and induced a martensitic phase transformation. The hardness of the surface layer of the modified 316L was twice the hardness of its matrix. The tensile strengths of 316L before and after UIT were 576 MPa and 703 MPa, respectively. The stretching stripes of 316L were more disordered after UIT. The fatigue strengths of 316L before and after UIT were 267 MPa and 327 MPa, respectively. The fatigue cracking of 316L started from the austenite grain boundaries. The fatigue fracture surface was relatively rough. The fatigue crack sources of the modified 316L came from internal inclusions. The inclusions were oxides dominated by SiO2. As the stress range increased, the crack initiation site migrated to the interior and the fatigue fracture surface became flatter. [ABSTRACT FROM AUTHOR]

In the present work, the hot deformation behavior of two austenitic stainless steels with different nitrogen is studied by conducting compression tests at the strain rates in the range 0.01–7 s−1 and temperatures in the range 950–1150 °C using a Gleeble thermomechanical simulator. Simultaneously, the constitutive relationship is based on the Arrhenius hyperbolic sine equation and constructs the corresponding thermal processing maps based on dynamic material modeling (DMM).The 23Cr7MnNi2Mo0.93N (0.93 N) steel possesses a higher hot deformation resistance and a higher activation energy of deformation (628.39 kJ mol−1) compared to the 23Cr7MnNi2Mo0.45N (0.45 N) steel (315.79 kJ mol−1). Dynamic recrystallization occurs predominantly in 0.93 N steels under the conditions tested, the samples with 0.93% nitrogen content exhibit higher peak stresses and more complex rheological behavior. According to the thermal processing maps, the hot working region for 0.45 N steel is 1020 to 1150 °C at strain rates of 0.01 to 0.1 s−1, while 0.93 N steel is not suitable for processing in the experimental parameter range. [ABSTRACT FROM AUTHOR]

In this study, we conducted in-situ tensile deformation tests using synchrotron X-ray and neutron diffraction techniques on Nb-bearing AISI 201 austenitic stainless steel specimens with varying grain sizes, including ultrafine (UFG, 0.28 μm), fine (FG, 1.75 μm), and coarse (CG, 110 μm) grains. The primary objective was to investigate the effect of grain size on the evolution of lattice strains and deformation mechanisms. Our findings reveal that grain size significantly impacts the evolution of lattice strains, peak broadening, and the distribution of load between the austenite and martensite phases. Notably, the average lattice strain and peak broadening were found to be higher in the CG specimen compared to the UFG and FG counterparts. While the lattice strains in the UFG and FG steels are all compressive, a tensile manner can be seen for the CG steel as deformation proceeds. The strain-induced martensite transformation kinetics for the reversion-annealed UFG and FG steels was higher than that of the solution-annealed CG one. A soft behavior from reflection (200) was found compared to other reflections in all UFG, FG, and CG specimens, showing anisotropic elastic properties. The analysis of lattice strain and peak broadening evolutions indicated that dislocation slip predominantly governs the deformation mechanism in the CG steel, while strain-induced martensitic transformation and twinning are more prominent in the UFG and FG specimens. [ABSTRACT FROM AUTHOR]

Super austenitic stainless steel 254SMO (254SMO SASS) plates are joined by double‐sided double‐arc synchronous TIP TIG butt welding (DSSTTABW) using ER NiCrMo3 wire, and the micro‐structure, mechanical and corrosion properties of 254SMO SASS joints are investigated subsequently. Results show that solidification grain boundary and solidification sub‐grain boundary can be observed in fusion zone. A small amount of σ phase precipitates in the weld, while χ phase is found in the transition zone, but no solidification crack occurs in weld and heat affected zone (HAZ). 254SMO SASS joint has higher micro‐hardness and lower tensile strength and elongation compared to base metal. During transverse tensile process, 254SMO SASS joints fail in the weld zone in a ductile mode. Electrochemical corrosion performance tests indicate that 254SMO SASS joint achieve equivalent pitting corrosion resistance and similar passive mechanism to base metal in 3.5 wt% NaCl solution. The passivation film on the surface of both joint and base metal display as n‐p semi‐conductive character, but the film stability of 254SMO joint surface is slightly poorer compared to base material. The surface passivation film of 254SMO joint primarily consists of oxides of Fe, Cr, and Mo before potentiodynamic polarization, while hydroxides of Fe and Cr are also observed after polarization. [ABSTRACT FROM AUTHOR]

With the growing interest in utilizing Mg and austenitic stainless steel (ASS) in the automotive sector, joining them together in three-sheet configuration is inevitable. However, achieving this task presents considerable challenges due to the large differences in their physical, metallurgical and mechanical properties. To overcome these challenges, the feasibility of using weld-bonding to join Mg alloy/ASS/ASS was investigated. The nugget formation, interface characteristics, microstructure and mechanical properties of the joints were investigated. The results show that the connection between the Mg alloy and upper ASS was achieved through the combined effect of the cured adhesive and weld-brazing in the weld zone. On the other hand, a metallurgical bond was formed at the ASS/ASS interface. The Mg nugget microstructure exhibited fine columar grains composed predominantly of primary α-Mg grains along with a eutectic mixture of α-Mg and β-Mg17Al12. The nugget formed at the ASS/ASS interface consisted largely of columnar grains of austenite, with some equiaxed dendritic grains formed at the centerline of the joint. The weld-bonded joints exhibited an average peak load and energy absorption of about 8.5 kN and 17 J, respectively (the conventional RSW joints failed with minimal or no load application). The failure mode of the joints changed with increasing welding current from interfacial failure via the Mg nugget/upper ASS interface to partial interfacial failure (part of the Mg nugget was pulled out of the Mg sheet). Both failure modes were accompanied by cohesive failure in the adhesive zone. [ABSTRACT FROM AUTHOR]

In this paper, a Cr coating was prepared by induction heating and pack-cementation chromizing on AISI 304 austenitic stainless steel. Then, the cold-rolling deformation and annealing treatment were introduced to refine the coarse matrix grains caused by pack-chromizing and improve the overall performance of 304 austenitic stainless steel. The phase composition, element distribution, and microstructure of the coating were carefully characterized. The microhardness, wear resistance, and corrosion resistance of the coating were tested. The results show that the Cr coating with a thickness of 100 μm is mainly composed of a (Cr,Fe)23C6, (Cr,Fe)7C3, and α-Fe-Cr solid solution. After the cold-rolling deformation and subsequent annealing treatment, the grains are significantly refined and the Cr coating is divided into two layers, consisting of carbon-chromium compounds such as Cr23C6, Cr7C3, Cr2C, and Cr3C2 in the surface layer and a Fe-Cr solid solution in the subsurface layer. The cold-rolling deformation and annealing treatment significantly improved the microhardness and wear resistance of the coated sample, and the corrosion resistance was also better than that of the uncoated sample. [ABSTRACT FROM AUTHOR]