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As-rolled Ti-22Al-24Nb-0.5Mo sheets were subjected to various solution treatment systems to improve their microstructural and mechanical properties. The effects of solution temperature and holding time on the evolution of microstructure, mechanical properties, and fracture behavior were analyzed. The analysis involves studying the variations in second-phase content, grain boundary evolution, globularization of the lath α2 phase, texture evolution, and changes in performance based on second-phase content and aspect ratio. Microstructure statistical analysis and mechanical property induction techniques were employed. Additionally, fracture mechanisms were identified through fracture behavior analysis. Microstructure evolution and tensile fracture models were constructed. Results indicate that the O phase rapidly dissolves in the B2 matrix within the temperature range of 990-1050 °C, leading to the globularization of the lath α2 phase. The proportion of low-angle grain boundaries and texture intensity peak at 1020 °C. The yield strength and elongation of nearly all the sheets significantly increase after solution treatment except at 1050 °C for 45 min. The brittle fracture characteristics of the sheets gradually manifest as the solution temperature increases. [ABSTRACT FROM AUTHOR]

By means of cold ring rolling (CRR), quenching and tempering treatments, microstructure observation, and mechanical‐property tests, the effects of CRR on the heat treatment microstructure and wear resistance of GCr15 bearing steel are studied. The results show that, CRR reduces the size of carbides in the spheroidized microstructure and increases their quantity. The carbide particle size before and after CRR are 1.264 and 0.697 μm, respectively. After solution treatment and quenching, the number of undissolved carbides significantly decreases in the CRR samples. When the solution treatment time is 20 min, the carbide size in the steel without and with CRR is 0.684 and 0.628 μm, indicating that CRR promotes carbide dissolution during solution treatment. After tempering, the CRR steel exhibits an increase in carbide precipitation, and a great number of particulate carbides are precipitated. The hardness of the CRR steel after tempering is notably enhanced, and the wear resistance is improved. When the solution treatment time is 15 min under the same quenching and tempering conditions, the CRR steel achieves the highest hardness of HRC 62.0 and the best wear resistance with the wear loss of only 4.73 × 10−5 mg (N m)−1. [ABSTRACT FROM AUTHOR]

The effects of different solution temperatures on the microstructure and corrosion resistance of graphene nanoplatelets reinforced A380 (A380-GNPs) composites were investigated. The results show that the grain size of the composites was significantly refined by adding 0.9 wt% GNPs, and most of the Si phases in the A380-0.9 GNPs composite after solution treatment at 505 °C were spheroidal. Energy dispersive spectroscopy analysis indicated that most of the Al2Cu phases have been dissolved into the matrix. The hardness of the 505 °C solution treated composites increased by 28.8% compared to the A380-0.9 GNPs composites. Immersion corrosion tests revealed that the corrosion rate of the 505 °C solution-treated A380-0.9 GNPs composites (46.76 μg cm−2 d−1) was 24.9% lower than that of the non-solution-treated (58.41 μg cm−2 d−1). Electrochemical analyses showed that the corrosion voltage of the 505 °C solution-treated composites (− 507.41 mV) was 7.4% higher than that of the non-solution-treated (− 548.76 mV). The 505 °C solution-treated A380-0.9 GNPs composites had a high surface-area ratio between the anodic phases (α-Al) and the cathodic phases (Al2Cu, Si), and the anodic corrosion current densities were relatively weak, which resulted in the best corrosion resistance. The refinement and uniform distribution of cathodic phases, such as Al2Cu and eutectic Si, inhibit the occurrence of micro-galvanic corrosion and also reduce the corrosion rate of the composites. [ABSTRACT FROM AUTHOR]

The precipitate dissolution and grain growth during the solution treatment of a newly developed Ce‐containing 15Cr–22Ni–1Nb steel are investigated. The dissolution of eutectic NbC is the result of the elements diffusion along the concentration gradients, and honeycomb (Fe,Cr,Ni,Si)2(Nb,Mo) Laves phase transforms into a more stable Mo2C‐type M2C carbide. As the cerium content is increased from 0 to 0.0630 mass%, the area fraction of eutectic precipitates in forged and solution‐treated 15Cr–22Ni steel is decreased first and then increased. For the steel with 0.0055 mass% cerium content, the substantial reduction in the area fraction of precipitates during hot forging and solution treatment is ascribed to the severe abnormal grain growth. In the case of 15Cr–22Ni steel with 0.0019 and 0.0630 mass% cerium content, the average size of austenite grains after solution treatment is reduced, the multipeak development of grain size distribution is restrained, the range of grain size distribution is narrowed, and the variation coefficient of grain growth, the critical size of abnormally grown grain, and the proportion of abnormally grown grain are all decreased. The variation coefficient of grain growth and the critical size of abnormally grown grain in the steel are increased as the solution time is extended, whereas the proportion of abnormally grown grain presents a general trend of reduction. The established mathematical model of grain growth in the paper can be well applied to predict and control the average size of austenite grains in 15Cr–22Ni steel after solution treatment. [ABSTRACT FROM AUTHOR]

This study was conducted on the quality control of Inconel625 alloy thin-walled structural components by CMT-WAAM (Cold Metal Transfer Based Wire and Arc Additive Manufacture) process. The solid solution + two-stage aging treatment process was proposed for the heat treatment of thin-walled parts. The effect of solid solution treatment temperature on the microstructure and mechanical properties of thin-walled parts was studied under the same aging treatment conditions. The experimental results show that the deposited microstructure of Inconel625 thin-walled structural parts is mainly columnar dendrites, which grow epitaxially along the deposition direction. The basic microstructure of specimen is γ-Ni solid solution, and many blocky or chain-like Laves phases are distributed in the grains and grain boundaries. After solid solution and two-stage aging treatment, the Laves phase of the specimen dissolves back, δ phase precipitates and significant changes in mechanical properties. With the increase of solution treatment temperature, the Laves phases dissolve gradually, accompanied by δ phases precipitation. As the solid solution treatment temperature increases, the Laves phase gradually dissolves back, accompanied by δ Phase precipitation. When the solid solution treatment temperature rises to 1200 °C, the Laves phase is completely dissolved, δ The phase disappears and the grain size significantly increases. As the solution treatment temperature increases, the microhardness and tensile strength show a trend of first increasing and then decreasing, while the yield strength shows no significant change. [ABSTRACT FROM AUTHOR]

Stress relaxation with synchronous aging (SRSA) could not only reduce springback but as well improve the performance of titanium alloy components. To reveal the relaxation mechanisms during SRSA, solution treatments of Ti-6.5Al–2Zr–1Mo–1V alloy under different temperatures were carried out to obtain diverse initial microstructures. The evolutions of microstructure including phase transformation, dislocation movement and stress-induced twinning were meticulously characterized. The progress of activation energy was analyzed quantitatively by the Kohlrausch-Williams-Watts equation. Results show that SRSA under all different conditions exhibits a rapid stress decline initially followed by a quasi-static stage, due to a shift in the driving force from stress-driven to thermally activated driven. The activation energy changes from a quasi-static state to a rapid rise with relaxation time. After two-phase solution treatment, the primary α (αp) dominant mechanism is the dislocation movement, including dislocation tangles and then recovery. The relaxation mechanism of the supersaturated metastable β phase is phase transformation (precipitation and growth of secondary α (αs)) and stress-induced twinning, and the αs realizes stress release through the globularization in the later stage. The full martensite microstructure was obtained by solution treatment in a single-phase region, and the main relaxation mechanism involves stacking faults, stress-induced twinning and then globularization. The enhancement in strength following SRSA is primarily attributed to the formation of αs, dislocation strengthening, and stress-induced twinning.

A novel non-magnetic Fe-21Cr-15Ni-5Mn-2Mo austenitic stainless steel with high strength and plasticity has been developed. The microstructure and liquid helium temperature (4.2 K) tensile properties of the top and bottom samples of large-size forged flat steel after solution treatment at 1090 °C were investigated. The results showed that the average grain size of the bottom sample (48.0 ± 6.7 μm) was smaller than that of the top sample (58.8 ± 15.3 μm), and the MX precipitates and Z phases were distributed in the matrix of the samples. The 4.2 K strengths of the samples at the top and bottom were high, and large amounts of annealing twin boundaries played a certain role in strengthening. After cryogenic tensile testing, large amounts of deformation twins, stacking faults, and dislocations were generated inside the austenite grains of both samples, which helped the material to obtain higher plasticity and strength. The top and bottom samples possessed excellent synergies of strength and plasticity at 4.2 K, and the 4.2 K tensile properties of the top sample were as follows: ultimate tensile strength (UTS) of 1850 MPa, yield strength (YS) of 1363 MPa, and elongation (EL) of 26%. The tested steel is thus believed to meet the requirements of combined excellent strength and plasticity within a deep cryogenic environment, and it would be a promising material candidate for manufacturing superconducting coil cases to serve in new generation fusion engineering. [ABSTRACT FROM AUTHOR]

To reveal the influences of solution temperature and Nd addition on microstructures and mechanical properties of Mg-12Gd-2Zn-xNd-0.4Zr (x = 0, 0.5, and 1 wt.%) alloys, optical microscope, scanning electron microscope, tensile testing machine, nano-indentation tester, and Vickers hardness tester were used to study the microstructures and mechanical properties of the solution-treated alloys. The results show that with the increase in solution temperature, the alternating α-Mg and β-(Mg, Zn)3Gd eutectic phase and the stacking faults (SFs) and long-period stacking ordered (LPSO) structures gradually decrease and disappear, accompanied by the increased needle-like precipitated phase. The β-(Mg, Zn)3Gd and needle-like precipitated phases increase with increasing Nd addition under the same solution temperature. The yield strength and elongation are both enhanced with increasing solution temperature, the yield strength is also improved but the elongation is reduced with increasing Nd addition. Most importantly, the comprehensive mechanical property, called product of strength and elongation, is significantly improved by increasing solution temperature for the three alloys, but overall, it is reduced with increasing Nd addition solution treated at the same temperature. The Mg-12Gd-2Zn-0.5Nd-0.4Zr solution treated at 515 °C shows the highest product of strength and elongation (4498.4 MPa%) with the ultimate tensile strength of 335.7 MPa and elongation of 13.4%. [ABSTRACT FROM AUTHOR]

Powder metallurgy is widely used to fabricate high-nitrogen, nickel-free austenitic stainless steel. However, after sintering and nitriding, additional solution treatment is typically required to achieve uniform nitrogen distribution and a homogeneous austenite phase. This work proposes a novel method to eliminate the need for lengthy and high-temperature solution treatment by switching the nitrogen atmosphere to argon during the cooling process. The effects of different N2-Ar atmosphere-switching temperatures (750–1320 °C) on the phase composition, element distribution, microstructure, mechanical properties, and corrosion resistance of the studied steels were systematically investigated. Results show that cooling in the N2 atmosphere initially transforms the matrix to a fully austenitic structure enriched with nitrogen. Excessive nitrogen infiltration leads to Cr2N precipitation, inducing partial austenite decomposition and forming a multiphase structure comprising austenite, α-Fe, and Cr2N. Strategic switching from N2 to Ar reverses this reaction, yielding a high-nitrogen, chemically uniform austenitic structure. Specifically, switching at 1150 °C, the steel exhibits excellent mechanical properties and corrosion resistance, with a yield strength of 749 MPa, an ultimate tensile strength of 1030 MPa, an elongation of 38.7%, and a corrosion current of 0.06 mA/cm2, outperforming the steels cooled solely in N2 and subsequently solution-treated. This novel method offers advantages in cost reduction, energy saving, and operational effectiveness, highlighting its potential for broad industrial application. [ABSTRACT FROM AUTHOR]

Copyright of Rare Metals is the property of Springer Nature 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 Iron Steel Vanadium Titanium is the property of Iron Steel Vanadium Titanium Editorial Office 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.)

This study was conducted to determine the indentation behavior of thin AlSi10Mg specimens manufactured using Selective Laser Melting (SLM) in the as-built condition along with two post-treatments, namely solution heat treatment and artificial aging. Four different thicknesses of 1.0 mm, 1.5 mm, 2 mm, and 2.5 mm of SLM specimens, with the different post-treatments, underwent standardized Rockwell hardness tests using a spherical indenter to determine their hardness values and assess the impression using a stereo microscope and scanning electron microscope (SEM). The as-built specimens showed a trend of smaller indentation depths with increasing specimen thickness, and finally creased with 0.1547 mm depth at 2.5 mm. However, the post-treatments altered the behavior of the specimens to a certain degree, giving larger experimental indentation depths of 0.2204 mm, 0.1962 mm, and 0.1798 mm at 1.0 mm, 1.5 mm, and 2.5 mm thickness, respectively, after solution heat treatment. Artificial aging showed a general decrease in indentation depth with increasing specimen thickness in contrast to solution treatment, and resulted in depths of 0.1888 mm and 0.1596 mm at 1.0 mm and 2.5 mm thickness. Furthermore, a material numerical model was made using stress–strain data on ANSYS Workbench to develop a predictive model for the indentation behavior of the specimens in contrast to experimentation. Under multi-linear isotropic hardening, the Finite Element Analysis (FEA) simulation produced indentation geometry with an average accuracy of 95.4% for the artificial aging series. [ABSTRACT FROM AUTHOR]

Aluminium 7075 is a material used to plane body, because this material is corrosion-resistant, and its properties can be formed well, low density and light. Aluminium 7075-T6 which is mainly used for aircraft manufacturing, has a content of 0,37% Zn, 0,13% Mg, 0,07% Cu and 0,20% Si. Because this material 7075-T6 is heat treatable. It will be treated with the solution treatment (420ºC) and aging treatment (250ºC) each in 1hour and 2,5 hours to make precipitation. The hight strength and low hardness to find out the characteristics of aluminium 7075-T6 tensile strength testing, hardness testing and EDS (Energy Dispersive X-Ray Spectroscopy) testing will be carried out. And the result of tensile strength testing for raw material has an ultimate tensile strength (125,000MPa), elongation (0,02%) and the result of Rockwell hardness testing has (10,36 HRt). This material done by processed solution treatment with temperature (420ºC/hour, 2,5 hours/ 150ºC) has an ultimate tensile strength (95,833 MPa), elongation (0,26%) and for the Rockwell hardness testing the result is (49,2 HRt). The heat treatment made the solution treated aluminium grain bigger but increasing the strength because of precipitation.

The low light absorption efficiency has seriously hindered the application of two-dimensional transition metal dichalcogenide (TMDC) nanosheets in the field of optoelectronic devices. Various approaches have been used to improve the performance of TMDC nanosheets. Preparation of one-dimensional TMDC nanoscrolls in combination with photoactive materials has been a promising method to improve their properties recently. In this work, we report a facile method to enhance the optoelectronic performance of TMDC nanoscrolls by wrapping the photoactive organic dye rhodamine (R6G) into them. After R6G molecules were deposited on monolayer TMDC nanosheets by the solution method, the R6G/MoS2 nanoscrolls with lengths up to hundreds of microns were prepared in a short time by dropping a mixture of ammonia and ethanol solution on the R6G/MoS2 nanosheets. The as-obtained R6G/MoS2 nanoscrolls were well characterized by optical microscopy, atomic force microscopy, Raman spectroscopy, and transmission electron microscopy to prove the encapsulation of R6G. There are multiple type II heterojunction interfaces in the R6G/MoS2 nanoscrolls, which can promote the generation of photo-induced carriers and the following electron–hole separation. The separated electrons were transported rapidly along the axial direction of the R6G/MoS2 nanoscrolls, which greatly improves the efficiency of light absorption and photoresponse. Under the irradiation of an incident 405 nm laser, the photoresponsivity, carrier mobility, external quantum efficiency, and detectivity of R6G/MoS2 nanoscrolls were enhanced to 66.07 A/W, 132.93 cm2V−1s−1, 20,261%, and 1.25 × 1012 cm·Hz1/2W−1, which are four orders of magnitude higher than those of monolayer MoS2 nanosheets. Our work indicates that the R6G/TMDC hybrid nanoscrolls could be promising materials for high-performance optoelectronic devices. [ABSTRACT FROM AUTHOR]

In this paper, the microstructure and mechanical properties of Al-6.5Si-5.5Cu-0.2Zr-0.01Sr-0.06Ti-0.2Ce cast aluminum alloys were investigated in multistage solid solution systems. The microstructure of the alloy was characterized using an optical microscope (OM), scanning electron microscope (SEM), energy-dispersive spectrometer (EDS), x-ray diffraction (XRD) and transmission electron microscope (TEM), respectively. The hardness and conductivity of the alloy were measured using a Vickers hardness and eddy current conductivity testers, respectively, and the tensile properties were described by a drawing machine. The results showed that the mechanical properties of the alloy are the worst under the four-stage solid solution system (G1). With the increase in multistage solution temperature and holding time, θ phase (Al2Cu) was gradually dissolved into α-Al matrix to enhance the effect of dislocation strengthening. When the solution temperature reached 510 °C, the mechanical properties of the alloy were the best, and the tensile strength and elongation were increased to 354.90 MPa and 9.02%, respectively. With the increase in temperature, eutectic Si agglomeration and large area of insoluble phase between metals were found, resulting in the decrease in mechanical properties. [ABSTRACT FROM AUTHOR]

This study investigates the influence of varying solution temperatures on the microstructure, texture, and anisotropic behavior of mechanical properties in TA10 (Ti-0.3Mo-0.8Ni). Solution treatment gradually transforms the microstructure of the titanium alloy plate from an elongated α phase to a nearly equiaxial phase and subsequently to a Widmanstatten microstructure. Concurrently, the texture intensity and type undergo significant alterations. The anisotropy of mechanical properties in the plate with a T-type texture ({0001}⊥ND) is notably higher than that in the plate with a nearly B-type texture ({0001}//ND), owing to differing slip system initiation difficulties. In particular, the anisotropy of the titanium alloy plate is not solely dependent on texture intensity and is also intricately linked to the texture type and distribution. Specifically, the prismatic texture {10 1 ¯ 0} < 11 2 ¯ 0 > plays a central role in influencing tensile strength and yield strength anisotropy, while the directionality of the α phase primarily contributes to elongation anisotropy. [ABSTRACT FROM AUTHOR]

The impact toughness of a few selected precipitation hardening aluminium alloys that have potential for vehicle armour applications is reported for the first time. It is observed that although the impact toughness is considerably higher in the solution heat-treated condition, it degrades with artificial ageing. The formation of weak grain boundaries in the artificially aged tempers is the major cause of poor impact toughness in these alloys. The impact toughness of commercially purity aluminium is reported for the first time within the context of the present work. [ABSTRACT FROM AUTHOR]

The abnormal grain growth (AGG) and strain behavior of friction stir welding (FSW) joints for a 6061 aluminum alloy subjected to various solution treatments was investigated using electron backscattering diffraction. The deformation storage energy derived from mechanical stirring was retained during solution treatment through strain inheritance. As a result of strain inheritance and grain size, exceedingly coarse grains possessing low strain and grain-orientation spread (GOS) values were formed by the abnormal growth of fine equiaxed grains possessing low strain and GOS values in the nugget zone (NZ). Owing to severe grain size inhomogeneity, AGG in the NZ of the FSW joints significantly decreased the mechanical properties and led to cleavage fracture of the tensile fracture surfaces. [ABSTRACT FROM AUTHOR]

This study introduces a new type of shear panel damper that utilizes iron-based shape memory alloy (Fe-SMA) with enhanced low-cycle fatigue (LCF) resistance for structural damage control, with a particular focus on the effect of solution treatment on the properties of interest of Fe-SMA. Material-level investigation was conducted first, aimed at establishing a clear connection between microscopic structure and macroscopic properties, and to determine the most suitable solution treatment method for Fe-SMAs for structural damping purposes. This was followed by laboratory tests on a Fe-SMA based shear panel damper receiving an appropriate solution treatment, along with conventional metal shear panel dampers made of low yield point steel LYP225 and mild steel Q235. Results reveal that among the considered solution treatments, 1,100°C for 1 h leads to the most desired mechanical properties, such as lower yield stress, increased ductility, and longer LCF life, of Fe-SMA for seismic damping applications. The Fe-SMA shear panel damper demonstrates a significant improvement in LCF life and total energy dissipation capacity compared to traditional steel dampers. Finally, detailed numerical investigations were carried out to analyze the seismic response. A calibrated micromechanics-based model, i.e., cyclic void growth model, was employed to predict the fracture initiation of the Fe-SMA shear panel damper under seismic loading. This approach achieved reasonable accuracy, assisting in understanding the distinctive behavior of Fe-SMA shear panel dampers. [ABSTRACT FROM AUTHOR]

Gravimetric weight loss analysis, response surface optimization, and predictive modeling techniques were used to study the corrosion resistance behavior of quenched Cu–Zn–Al alloys in 0.5 m HCl solution. Cu–Zn–Al alloy with 20 and 6 weight percent Zn and Al respectively, was developed by casting method. Prior to being machined to specifications for the corrosion resistance test, the alloy underwent a solutionizing treatment at 850 °C. During the corrosion weight loss measurement, the immersion time and operation temperature ranged from 1 to 4 h and 35 to 60 °C respectively. The corrosion rate of the solution-treated Cu–20Zn–6Al alloy in 0.5 m HCl dropped from 120.189 to 1.603 mm/year with increasing operation temperature and immersion time, according to the corrosion test findings. Thus the Cu–Zn–Al alloy demonstrated strong resistance to corrosion in 0.5 m HCl solution within the boundaries of the considered process parameters. RSM optimization of the experimental process revealed that all the generated model terms are significant with P values less than 0.05. Derived regression model capable of predicting the optimal corrosion rate correlates the corrosion immersion time and operating temperature with the corrosion rate of the solution-treated Cu–20Zn–6Al alloy within the studied conditions. Numerical optimization of the process parameters reveal that at 60 °C and 4 h maximum operating temperature and immersion time, minimal corrosion rate with 0.990 high degree of desirability would be obtained. The as-quenched Cu–20Zn–6Al alloy could be applied in the design of components for elevated temperature acidic environments. [ABSTRACT FROM AUTHOR]

2205 Duplex Stainless Steel (DSS) is extensively utilized in various structural components due to its exceptional strength and corrosion resistance. However, for complex structural parts that are challenging to process using conventional methods, Selective Laser Melting (SLM) technology offers a viable solution by enabling layer-by-layer solidification. The rapid cooling rates during the forming process effectively suppress the precipitation of detrimental brittle phases like σ, while concurrently promoting a high proportion of ferrite phases within the structure upon cooling to room temperature. This paper investigates the microstructure and properties of 2205 DSS fabricated via SLM. A notable observation was the presence of abundant precipitates along the ferrite grain boundaries. Characterization through Energy-Dispersive X-ray Spectroscopy (EDS) and Transmission Electron Microscopy (TEM) confirmed the presence of χ-phase and nanoscale closely packed hexagonal Cr2N-phase precipitates. The high fault density and precipitates induced by the SLM process significantly enhanced the sample's strength, resulting in a remarkable tensile strength of 1301.69 ± 19.6 MPa and yield strength of 781.2 ± 12.2 MPa. Subsequent cooling via solid solution water treatment at 1050°C yielded a biphase structure with an austenite content of 54.7% and ferrite content of 45 %. The tensile strength decreased to 815.61 ± 16.4 MPa, and the yield strength decreased to 443.245 ± 7.5 MPa, while the elongation increased significantly from 19.03 ± 1.2% to 46.53 ± 0.7%. These findings demonstrate that the material achieved performance levels comparable to forging and hot rolling processes.

The usage of Mg–Al–Zn alloys for lithium-ion battery shell is able to achieve further lightweight of electric vehicles, and their corrosion resistance would highly determine the service life. In this work, therefore, a Y-modified AZ91 magnesium alloy (AZ91-0.5Y) was first prepared by conventional casting and following hot extrusion, and the influence of solution treatment (ST) and subsequent pre-deformation (SP) treatments on its electrochemical corrosion and stress corrosion cracking (SCC) resistance in 1 mol/L LiPF6 electrolyte were then investigated. The results indicated that the presence of large lamellar or rod-like β-Mg17Al12 phase in as-extruded AZ91-0.5Y alloy would lead to serious micro-galvanic corrosion and SCC. After solution treatment, the β-Mg17Al12 phase almost completely dissolved into Mg matrix, weakening the micro-galvanic corrosion and anodic dissolution (AD) and hydrogen embrittlement (HE) effect. Further, the subsequent pre-deformation treatment could introduce dislocation, more precipitation of Al2Y phase, massive twins and optimized texture, leading to the improved corrosion resistance and mechanical strength as well as the formation of well-integrated protective corrosion product film MgF2 with low porosity. As a result, the corrosion and SCC resistance of as-extruded, ST and SP specimens is ordered from low to high.

This study aims to investigate the effect of hot deformation on commercially available Ti-6246 alloy below its β-transus transition temperature at 900 °C, knowing that the α → β transition temperature of Ti-6246 alloy is about 935 °C. The study systematically applies a thermomechanical processing cycle, including hot rolling at 900 °C and solution and ageing treatments at various temperatures, to investigate microstructural and mechanical alterations. The solution treatments are performed at temperatures of 800 °C, 900 °C and 1000 °C, i.e., below and above the β-transus transition temperature, for 9 min, followed by oil quenching. The ageing treatment is performed at 600 °C for 6 h, followed by air quenching. Employing various techniques, such as X-ray diffraction, scanning electron microscopy, optical microscopy, tensile strength and microhardness testing, the research identifies crucial changes in the alloy's constituent phases and morphology during thermomechanical processing. In solution treatment conditions, it was found that at temperatures of 800 °C and 900 °C, the α′-Ti martensite phase was generated in the primary α-Ti phase according to Burger's relation, but the recrystallization process was preferred at a temperature of 900 °C, while at a temperature of 1000 °C, the α″-Ti martensite phase was generated in the primary β-Ti phase according to Burger's relation. The ageing treatment conditions cause the α′-Ti/α″-Ti martensite phases to revert to their α-Ti/β-Ti primary phases. The mechanical properties, in terms of strength and ductility, underwent an important beneficial evolution when applying solution treatment, followed by ageing treatment, which provided an optimal mixture of strength and ductility. This paper provides engineers with the opportunity to understand the mechanical performance of Ti-6246 alloy under applied stresses and to improve its applications by designing highly efficient components, particularly military engine components, ultimately contributing to advances in technology and materials science. [ABSTRACT FROM AUTHOR]

In this study, TiC x -Cu (x = 0.5, 0.6, 0.7) cermets were prepared combined with subsequent solution treatment, and the influences of solution treatment on the microstructures and mechanical properties were analyzed. The fracture mechanisms of cermets before and after solution treatment were mainly observed and analyzed. The results show that solution treatment can significantly improve the comprehensive mechanical properties of TiC x -Cu cermets. The fracture toughness K IC of TiC 0.5 -Cu and TiC 0.7 -Cu cermets increased by 28% and 11%, respectively. The improvements of the comprehensive properties of TiC x -Cu cermets were benefited by the reduction of the content of hard brittle intermetallic compound Cu 4 Ti and the refinements of the grain size of Cu. [ABSTRACT FROM AUTHOR]

The effects of solution treatment on the corrosion resistance and cytocompatibility of micro-arc oxidation (MAO) coating on biodegradable Mg-2Zn-1Gd-0.5Zr alloy were studied in this work. Microstructural characterization, coating adhesion, electrochemical, immersion and cytocompatibility tests were carried out. The results demonstrated that the MAO coating was much more uniform after solution treatment with coating adhesion enhanced by about 30% compared with the as-extruded + MAO coated. Moreover, the corrosion resistance of the solution treated + MAO coated samples was respectively improved by more than 20% and twice, compared with as-extruded + MAO coated and as-extruded samples. In addition, solution treatment further improved the cell viability of the MAO coating of the alloy with the RGR exceeding 90% during the entire culture period with MG63 cells. Consequently, solution treatment is recommended as a preferred pretreatment for improving the corrosion resistance and cytocompatibity of MAO-coated Mg alloys. [ABSTRACT FROM AUTHOR]

The study presented in this paper is focused on the effect of varying the solution treatment duration on both the microstructural and mechanical properties of a cold-deformed by rolling Ti-30Nb-12Zr-5Ta-2Sn-1.25Fe (wt.%) alloy, referred to as TNZTSF. Cold-crucible induction using the levitation synthesis technique, conducted under an argon-controlled atmosphere, was employed to fabricate the TNZTSF alloy. After synthesis, the alloy underwent cold deformation by rolling, reaching a total deformation degree (total applied thickness reduction) of 60%. Subsequently, a solution treatment was conducted at 850 °C, with varying treatment durations ranging from 2 to 30 min in 2 min increments. X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques were utilized for the structural analysis, while the mechanical properties were assessed using both tensile and hardness testing. The findings indicate that (i) in both the cold-deformed-by-rolling and solution-treated states, the TNZTSF alloy exhibits a microstructure consisting of a single β-Ti phase; (ii) in the solution-treated state, the microstructure reveals a rise in the average grain size and a decline in the internal average microstrain as the duration of the solution treatment increases; and (iii) owing to the β-phase stability, a favorable mix of elevated strength and considerable ductility properties can be achieved. [ABSTRACT FROM AUTHOR]

Thin twin-roll cast strips from a model Al-Cu-Mg-Li-Zr alloy with a small addition of Sc were prepared. A combination of a fast solidification rate and a favorable effect of Sc microalloying refines the grain size and the size of primary phase particles and reduces eutectic cell dimensions to 10–15 μ m. Long-term homogenization annealings used in conventionally cast materials lasting several tens of hours followed by a necessary dimension reduction through rolling/extruding could be substituted by energy and material-saving procedure. It consists of two-step short annealings at 300 °C/30 min and 450 °C/30 min, followed by the refinement and hardening of the structure using constrained groove pressing. A dense dispersion of 10–20 nm spherical Al 3 (Sc , Zr) precipitates intensively forms during this treatment and effectively stabilizes the structure and inhibits the grain growth during subsequent solution treatment at 530 °C/30 min. Small (3%) pre-straining after quenching assures more uniform precipitation of strengthening Al 2 Cu ( θ ′ ), Al 2 CuMg ( S ′ ), and Al2CuLi ( T 1 ) particles during subsequent age-hardening annealing at 180 °C/14 h. The material does not contain a directional and anisotropic structure unavoidable in rolled or extruded sheets. The proposed procedure thus represents a model near net shape processing strategy for manufacturing lightweight high-strength sheets for cryogenic applications in aeronautics. [ABSTRACT FROM AUTHOR]

In the present study, the effects of varying heating and cooling rates during the solution treatment process on the microstructure and properties of AA7050 alloy wires were investigated using tensile tests, metallographic microscopy, electron backscattered diffraction, and transmission electron microscopy. It was found that the recrystallized grain size of the alloy, subjected to method of rapid heating, exhibited a smaller and more uniform distribution in comparison to method of slow heating. The low density of η′ strengthening phases after the artificial aging treatment was formed using air cooling method. Meanwhile, by using the water quenching method sufficient solute atoms and more nucleation sites were provided resulting in a large number of η′ strengthening phases being formed. In addition, the alloy processed using the water quenching method displayed higher strength than that treated using the air cooling method for the T6 and T73 states. Furthermore, coarse precipitates formed and less clusters were observed in the matrix, while high density nanoscale clusters and no continuous precipitation are formed when using the water quenching method. [ABSTRACT FROM AUTHOR]

In this study, a systematic investigation on the effect of solution treatment time (2–8 h) at 540 °C on the microstructure and mechanical properties in as-cast Mg-1Al-12Y (AY112, wt.%) alloy was performed. The results showed that the solution treatment did not cause the growth of grains and the change of texture; however, the mechanical properties had been significantly improved, which was mainly attributed to the precipitation of 18R long period ordered stacking (LPSO) phase in the solution-treated alloys. In addition, the dissolution of β-Mg24Y5 phase and the diffusion of solute atoms during the solution treatment were both beneficial to the mechanical properties. When the as-cast alloy was solution-treated at 540°C for 4 h (T4-4h alloy), the mechanical properties of the alloy are optimal. Compared with the as-cast alloy, the ultimate tensile strength (UTS) and elongation of the T4-4h alloy are increased by ∼23% and ∼179%, respectively. The deformation of the T4-4h alloys was dominated by a combination of basal slip and non-basal slip, and the presence of the LPSO phase effectively inhibited the nucleation of extension twin. Besides, the LPSO phase can also hinder the activation of basal dislocations and the movement of non-basal dislocations. Therefore, the LPSO phase simultaneously improves the strength and plasticity of the alloy.

GH2132 alloy， as one of the representative materials of high-temperature alloys based on Fe-25Ni-15Cr，has become a widely used high-temperature material below 650 ℃ due to its excellent comprehensive properties. At present，the research on GH2132 alloy mainly focuses on three aspects： solid solution heat treatment，solid solution + aging heat treatment，and direct aging heat treatment. This article summarizes recent research on the alloy in these three aspects and analyzes the impact of heat treatment processes on microstructure and properties. During the solid solution treatment process of GH2132 alloy，attention should be paid to the effect of the dissolution of Laves and M3B2 phases on grain size to prevent grain coarsening. The alloy after solid solution exhibits the characteristics of low strength and high plasticity. The formulation of aging treatment process needs to be combined with solid solution treatment process，taking into account the influence of coupling effect and preventing occurrence γ′ → η transform and reduce the reinforcement effect. The microstructure of GH2132 alloy is sensitive to deformation，and the larger the deformation，the lower the aging temperature or shorter the aging time should be chosen.

The hot-rolled Al-Zn-Mg-Cu system aluminum alloy was treated with single-stage solution，low temperature-long term & high temperature-short term and low temperature-short term & high temperature-long term，double-stage solution quenching systems. The effects of different solution methods on the structure and properties of Al-Zn-Mg-Cu system aluminum alloy were systematically compared and analyzed by OM，SEM，DSC，EBSD and other technical means，as well as conductivity testing methods. The results show that the selected solution quenching system will not cause the structure to overheat，and can fully dissolve the eutectic second phase of the low melting point in the structure. When 473 ℃/20 min+477 ℃/40 min two-stage solution quenching system is selected，the plate has the best solution effect and the lowest conductivity，which is 27.60%IACS，and the recrystallization degree of the structure is less than 50%. There are {112}〈111〉，{011}〈211〉，{123}〈634〉 deformation texture and {001}〈110〉 shear texture in the structure.

Powder metallurgy is widely used to fabricate high-nitrogen, nickel-free austenitic stainless steel. However, after sintering and nitriding, additional solution treatment is typically required to achieve uniform nitrogen distribution and a homogeneous austenite phase. This work proposes a novel method to eliminate the need for lengthy and high-temperature solution treatment by switching the nitrogen atmosphere to argon during the cooling process. The effects of different N2-Ar atmosphere-switching temperatures (750–1320 °C) on the phase composition, element distribution, microstructure, mechanical properties, and corrosion resistance of the studied steels were systematically investigated. Results show that cooling in the N2 atmosphere initially transforms the matrix to a fully austenitic structure enriched with nitrogen. Excessive nitrogen infiltration leads to Cr2N precipitation, inducing partial austenite decomposition and forming a multiphase structure comprising austenite, α-Fe, and Cr2N. Strategic switching from N2 to Ar reverses this reaction, yielding a high-nitrogen, chemically uniform austenitic structure. Specifically, switching at 1150 °C, the steel exhibits excellent mechanical properties and corrosion resistance, with a yield strength of 749 MPa, an ultimate tensile strength of 1030 MPa, an elongation of 38.7%, and a corrosion current of 0.06 mA/cm2, outperforming the steels cooled solely in N2 and subsequently solution-treated. This novel method offers advantages in cost reduction, energy saving, and operational effectiveness, highlighting its potential for broad industrial application.

This study investigated the effects of solution treatment (ST) on the microstructure and mechanical properties of (SiC+TiB2)/Al–Zn–Mg–Cu composite produced using laser powder bed fusion (LPBF). Microstructural analysis reveals that the grid-like distribution of eutectic precipitates within the as-printed composite disappeared, giving way to the formation of uniformly distributed precipitates. As the ST temperature increased, the content of spherical Si particles decreased, while the content of elongated Al4SiC4 precipitates increased. Matrix grains recrystallization occurred, resulting in a gradual increase in the average grain size from 3.79 μm to 5.23 μm. The preferred crystallographic orientation features along the printing direction, {001} plate texture, were weakened, gradually exhibiting a more disordered growth. The microhardness and tensile strength of the composites exhibited a slight decrease and exhibited a trend of initially increasing and then decreasing with increasing ST temperature. Additionally, the heterogeneity in microhardness along different directions has been reduced. When the ST temperature was 460 °C, the elongation of the composite experienced a significant increase, escalating from 6.12 ± 0.36% to 10.3 ± 0.25%. However, with the increase in ST temperature, it displayed an obvious downward trend. The maximum tensile strength was 449 ± 8 MPa, and the elongation was 9.6 ± 0.4% with the ST temperature of 500 °C. The variations in mechanical properties were primarily attributed to the elimination of grid-like substructure, the uniform distribution of precipitates, and the gradual coarsening of grains. This research was expected to contribute to developing advanced lightweight materials with improved performance, opening up new opportunities for their application in various industries.

The 316L/430 duplex stainless steels were prepared by selective laser melting in this study, using 316L and 430 mixed powders prepared by gas atomization as the raw materials. The microstructure, mechanical properties, and corrosion resistance of the 316L/430 duplex stainless steels before and after solution treatment were examined by optical microscope, electronic material testing machine, and electrochemical workstation. The results indicate that, as the solution temperature is 1250 ℃, the 316L/430 duplex stainless steels specimens show the better comprehensive mechanical properties, the tensile strength, yield strength, elongation, and microhardness are 830 MPa, 340 MPa, 25%, and HV 356, respectively, and the area ratio of ferrite to austenite is 45.7:54.3. When the solution temperature is 1150 ℃, the specimens have the better corrosion resistance, the self-corrosion current density and pitting potential are 3.196×10‒6 A/cm2 and −0.118 V, respectively.

In the present study, we investigated the effects of solution treatment and friction stir back extrusion on the microstructure, mechanical properties, and in-vitro corrosion behavior of the AZ91/64SiO2–31CaO–5P2O5 composite. The findings demonstrate that the reinforcing phase of bioactive glass in the AZ91 matrix exhibits a gradient distribution, resulting in grain refinement in the zone near the surface of the composite wire. The fabrication of the AZ91-3 vol% bioactive glass composite through friction stir back extrusion, utilizing a rotational speed of 1200 rpm and an extrusion speed of 20 mm/min, leads to a significant improvement in corrosion resistance compared to the solid solutionized AZ91 alloy, as demonstrated by a ∼93% increase in simulated body fluid (SBF). During the friction stir back extrusion of the solid solutionized AZ91 alloy, heat and plastic deformation result in the re-precipitation of the ß-Mg17Al12 phase in the α-Mg matrix. The presence of bioactive glass particles facilitates this re-precipitation process during friction stir back extrusion. In comparison to the solid solutionized AZ91 alloy, the AZ91-3 vol% bioactive glass composite exhibits a 23% increase in ultimate tensile strength (UTS), a 28% increase in yield strength (YS), and a 30% decrease in elongation.

This paper examines the optimal aging temperature of WE43 alloy that has undergone precipitation hardening in conjunction with deep cryogenic treatment. The microstructure and phase composition were investigated, a microanalysis of the chemical composition was performed, and instrumental indentation tests were performed to determine the parameters of the micro-mechanical properties of the alloy after different heat treatment variants. It has been proven that a decrease in the aging temperature from 250 °C to 225 °C and the introduction of a deep cryogenic treatment lead to favorable changes in the microstructure of the alloy (reduction in grain size, increase in the number, and change in the type of β-phase precipitates). The changes in the alloy structure achieved by lowering the aging temperature contribute to the improvement of the micromechanical properties of the test material. The most advantageous results were recorded for an alloy subjected to solution treatment and aged at 225 °C for 24 h with deep cryogenic treatment: a 30% increase in hardness, a 10% increase in Young's modulus, an improvement in elastic properties, and increased resistance to deformation of the alloy were shown compared to the initial (as-received) state. Raising the aging temperature to 250 °C leads to a phenomenon known as alloy overaging for both alloys after classical precipitation hardening and after deep cryogenic treatment. The results indicate the significant effectiveness of the proposed heat treatment in improving the service life of the Mg-Y-Nd-Zr (WE43) alloy. [ABSTRACT FROM AUTHOR]

In this study, a systematic investigation on the effect of solution treatment time (2–8 h) at 540 °C on the microstructure and mechanical properties in as-cast Mg-1Al-12Y (AY112, wt.%) alloy was performed. The results showed that the solution treatment did not cause the growth of grains and the change of texture; however, the mechanical properties had been significantly improved, which was mainly attributed to the precipitation of 18R long period ordered stacking (LPSO) phase in the solution-treated alloys. In addition, the dissolution of β-Mg 24 Y 5 phase and the diffusion of solute atoms during the solution treatment were both beneficial to the mechanical properties. When the as-cast alloy was solution-treated at 540°C for 4 h (T4-4h alloy), the mechanical properties of the alloy are optimal. Compared with the as-cast alloy, the ultimate tensile strength (UTS) and elongation of the T4-4h alloy are increased by ∼23% and ∼179%, respectively. The deformation of the T4-4h alloys was dominated by a combination of basal slip and non-basal slip, and the presence of the LPSO phase effectively inhibited the nucleation of extension twin. Besides, the LPSO phase can also hinder the activation of basal dislocations and the movement of non-basal dislocations. Therefore, the LPSO phase simultaneously improves the strength and plasticity of the alloy. [ABSTRACT FROM AUTHOR]

Effect of different Mn and Mo contents on microstructure and mechanical properties of Al-Si-Cu-Mg-0.6Fe alloy was studied. Results indicate that the increase of Mo and decrease of Mn lead to a decrease in the size of the α-Al15(FeMnMo)3Si2 phase formed during solidification. The α-Al15(FeMnMo)3Si2 phase reaches a minimum value of about 16.3 µm at 0.2wt.% Mo and 0.1wt.% Mn addition. After solution treatment, the α-Al(FeMnMo)Si dispersed phase is precipitated. When only Mn is added, the α-Al(FeMnMo)Si dispersed phase mainly distributes near the grain boundaries, while when only Mo is added, it primarily distributes in the central region of the matrix. When both Mn and Mo are added, the dispersed phase has a larger and denser dispersed region and is uniformly distributed near the Al matrix and grain boundaries. Moreover, the best overall mechanical properties of the alloy are obtained with the combined addition of 0.1wt.% Mn and 0.2wt.% Mo, due to the smaller size of α-Al15(FeMnMo)3Si2 phase and the larger area fraction and higher density of the α-Al(FeMnMo)Si dispersed phase. The yield strength, ultimate tensile strength, and elongation are respectively improved 67.7 MPa, 48.5 MPa and 5.3%, respectively, compared to that of the alloy with only 0.3wt.% Mn. [ABSTRACT FROM AUTHOR]

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A novel versatile ultrahigh-strength stainless bearing steel was prepared by first solution treating the steel at temperatures between 1000 °C and 1100 °C for 1 h, followed by performing cryogenic treatment at −73 °C for 2 h, and tempering at 500 °C for 2 h, with the cryogenic and tempering treatments being repeated twice. The microstructures were characterized using multiscale techniques, and the mechanical properties were investigated using tensile testing, as well as via Rockwell hardness and impact toughness measurements. Tensile strength was found to be independent of solution temperature, with a value of about 1800 MPa. In contrast, yield strength decreased from 1530 MPa to 1033 MPa with increasing solution temperature, while tensile elongation increased from 15.3% to 20.5%. This resulted in an excellent combined product of tensile strength and elongation for steels initially treated at 1080 °C and 1100 °C, with values of 33.9 GPa·% and 37.0 GPa·%, respectively. Furthermore, the steels showed excellent impact toughness, increasing from 37.0 J to 86.2 J with increasing solution temperature. The microstructural and mechanical investigations reveal that the excellent mechanical properties and impact toughness are related to three factors, namely (i) a transformation-induced plasticity effect, mainly attributed to a high volume fraction of retained austenite, (ii) a high strengthening capacity arising from a high dislocation density, and (iii) a synergistic effect due to cobalt additions and the nanoprecipitation of M2C and M6C carbides. [ABSTRACT FROM AUTHOR]