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TiN nano-layered thin films were synthesized using an indigenously built cylindrical magnetron sputtering (CMS) apparatus at varying nitrogen flow rates ranging between 5 and 45 sccm at a constant deposition pressure of 9.5 × 10−2 mbar. Grazing incidence X-ray diffraction (GIXRD), atomic force microscopy (AFM), laser Raman spectroscopy (LRS), and nano-indentation studies were performed to characterize these as-deposited films. Unlike conventional sputtering, CMS grown films exhibited Stranski–Krastanov (SK) growth with self-assembled nano-hill architecture. The growth of nano-hills is attributed to the shadowing effect of oblique incident flux arising from cylindrical shaped cathode. Additional relaxation based on inverse Hall–Petch formalism brings about indentation induced buckling of nano-hills leading to softening of the TiN films. Higher hill heights at lower nitrogen flow led to increased friction and wear as they are crushed under the applied load generating debris. In contrast, the shorter nano-hills at high nitrogen flow tend to buckle rather than collapse under indenter load resulting in reduced friction. Coefficient of friction value is further influenced by the angle between nano-hill arrays, growth orientation, and indenter sliding directions. Raman spectroscopy data shows the appearance of high wave number anti-symmetric A + O mode for films synthesized at higher argon or nitrogen concentrations. [ABSTRACT FROM AUTHOR]

Monolithic thin structures have wide range of applications in aerospace and automobile sectors. Fabrication of thin monolithic structures is a challenge owing to their inherent lack of static and dynamic stiffness. Overall quality and acceptability of the product is hampered by forced vibrations associated with the machining of thin structures. In the past, good machined thin structure was realized only by adding stiffness to the structure, operating at high speeds and within dynamic stable limits of the machine tool. Altering tool design and tool trajectories bore limited success. In the present work, chatter free machined surface was realized by employing a novel method of relieved shank tooling (for peripheral milling), by adding stiffness (for face milling) at conventional cutting speeds. Relieved shank tooling provides a certain gap between the tool and the vibrating machined thin structure at the free end. Apart from realization of chatter free machined surface at all the operating parameters, experimental insights on the effect of cutting parameters on surface roughness, surface residual stresses induced and the subsequent corrosion on the thin machined surface of aluminum 6061-T6 at conventional machining parameters have been presented. Surface quality improves by nearly 100% with nearly three times increase (from 80 to 280 m/min) in cutting speed and reduction in feed (from 0.64 to 0.16 m/min) at conventional range. Subsequent corrosion studies revealed reduction by nearly 60% (especially at lower cutting speeds) for surface machined by relieved shank tool in comparison with conventional tool. [ABSTRACT FROM AUTHOR]

Herein, we report the methodological impact on the curing kinetics of bone cement based on polymer nanocomposites prepared using different methods. Poly (styrene-co-methylmethacrylate)–2D nanofiller nanocomposites (P(S-MMA)–2D Nanofiller) were prepared using bulk and suspension polymerization methods to study the effect of the different methods. The prepared nanocomposites were well-characterized for chemical, thermal, mechanical, and structural characteristics using Fourier Transform Infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), nano-indentation, and scanning electron microscopy (SEM) techniques, respectively. The FT-IR results confirmed the successful formation of the polymer nanocomposites. The DSC results showed that the prepared nanocomposites have higher thermal stabilities than their copolymer counterparts. The nano-indentation results revealed that the elastic modulus of the copolymer nanocomposites (bulk polymerization) was as high as 7.89 GPa, and the hardness was 0.219 GPa. Incorporating the 2D nanofiller in the copolymer matrix synergistically enhances the thermo-mechanical properties of the bone cement samples. The polymer nanocomposites prepared using the suspension polymerization method exhibit faster-curing kinetics (15 min) than those prepared using the bulk polymerization (120–240 min) method. [ABSTRACT FROM AUTHOR]

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The present study deals with the development and characterization of Mo-35Ti-10Si and Mo-35Ti-10Si-2B (wt.%) alloy for ultra-high temperature applications beyond the temperature limit of existing super alloys. The microstructural characterization using scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), electron back scattered diffraction (EBSD), x-ray diffraction (XRD) revealed that the Mo-35Ti-10Si-2B alloy was consisted of three phases, namely, (Mo, Ti)ss, (Mo, Ti)5SiB2 and (Ti, Mo)5Si3; whereas, Mo-35Ti-10Si alloy was found to be consisting of (Mo, Ti)ss, and (Mo,Ti)3Si phases. Since quantification of boron is difficult by EDS, Particle Induced Gamma-ray Emission (PIGE), a nuclear reaction analysis technique was used for chemical composition analysis of boron. The oxidation behavior of the Mo-35Ti-10Si-2B alloy in the temperature regime of 825-1250 °C was studied in detail and compared with boron-free Mo-35Ti-10Si alloy. Mo-35Ti-10Si-2B alloy exhibited superior oxidation behavior at intermediate temperatures of 825 °C, and excellent oxidation resistance at higher temperatures between 1000 and 1250 °C due to the formation of the protective borosilica and double oxide layers (TiO2 and duplex borosilica-TiO2), respectively. High-temperature oxidation mechanisms were discussed using detailed microstructural cross section analysis of the oxidized alloy samples. The micro-mechanical behavior of constitutive phases of the Mo-35Ti-10Si-2B alloy were studied by microhardness, nano-indentation and micropillar compression testing. The micropillar compression of (Mo, Ti)ss phase showed fairly ductile behavior with the evidence of activation of dislocation in the form of slip lines revealed through the post-deformation fractography. Deformation studies of (Mo, Ti)5SiB2 and (Ti, Mo)5Si3 phases were also carried out which showed large strain bursts indicating possibility of activation of dislocation activities even at room temperatures imparting low level of ductility. [ABSTRACT FROM AUTHOR]

Nano‐twinned Cu pillar is fabricated on an as‐electroplated nano‐twinned Cu film, which preferentially grew in the {111} plane family. With a nano‐indentation device (Picoindenter), a vertical ultrahigh pressure of 5100 MPa is applied to the nano‐twinned Cu pillar. The twin lamellar grain is greatly deformed under that ultrahigh external stress. Consequently, the top surface plane is pressed into the lattice beneath to continuously form edge dislocations. Those dislocations are driven along the possible slip systems toward the outer surface of the first matrix lamella, corresponding to the plastic deformation. A dislocation‐mediated mechanism is proposed to explain the plastic deformation of the nano‐twinned Cu pillar. Three types of slip systems are identified for the created dislocations, each resulting in either the displacement on the first matrix lamellar grain or cross‐slip on the twin boundary. At the ultrahigh external pressure, as the dislocations slide through the twin boundary, they would dissociate to Shockley partial dislocations and alter the stacking sequence in the twin boundary, creating stacking faults. The resultant stacking faults in the twin boundary are observed in the transmission electro microscopy (TEM) lattice images. [ABSTRACT FROM AUTHOR]

Recent advancements in additive manufacturing (AM) fuel efforts for expanding the design envelopes for components obtained via this technology through continuous improvement in mechanical behavior. Damping properties can also be altered depending on the microstructure evolved during AM. Therefore, achieving enhanced monotonic mechanical response with better damping properties is highly sought-after. In this respect, thermo-mechanical processing via severe plastic deformation (SPD) and artificial aging is imparted on the additive-manufactured samples with the target of grain refinement and densification to further improve mechanical and damping properties. Employing microstructural characterizations and mechanical experiments, a multi-scale exploration is carried out to develop a relation between the evolved microstructure and the resulting behavior. It is concluded that introducing a refined microstructure decorated with well-distributed (Mg,Si)-rich phase and favorable dislocation substructure in AlSi10Mg positively affects the resulting mechanical behavior. Moreover, it is shown that artificial aging can be employed to improve the damping characteristics of severely deformed additive-manufactured AlSi10Mg alloy. [ABSTRACT FROM AUTHOR]

In the present research study, the tribological characterization of cobalt (Co) and boron nitride (BN) coating was carried out at the nanoscale level. A single-layered nano-coating with a thickness of 500 nm was deposited on the Al-Si substrate by using solid targets of cobalt and boron nitride. The structural analysis and surface morphology of Co-BN coatings was characterized by using field emission scanning electron microscope (FESEM), energy-dispersive spectroscopy (EDS) and x-ray diffraction (XRD). Nano-hardness tests were carried out to study the effect of load on Hardness (H) and Young's modulus (E). The tribological properties of Co-BN coatings were carried out to investigate the deformation and failure behavior of the coating/substrate. It was observed that Co-BN particulates were uniform and compact without cracks and homogeneously distributed within the coating. The results showed that the hardness and Young's modulus of Co-BN coating decreased with an increase in load. It was also observed that Co-BN coating adheres well to the substrate and showed good lubricating characteristics with a coefficient of friction (COF) varying from 0.2 to 0.5. The wear resistance of Co-BN coating increased from 4.22 × 10-6 to 1.56 × 10−5 mm3/m as the load increased from 0.5 to 2 N. The results of this study indicate that Co-BN coatings developed by magnetron sputtering show better nanomechanical and tribological properties and can be used efficiently as a solid lubricating coating and in aerospace applications. [ABSTRACT FROM AUTHOR]

The study investigates the role of different laser energy densities on the micro-structural evolution in the laser surface re-melted as-cast Zr-8 wt% Cu alloy. In the current study, different values of laser energy density was achieved by varying the scan speeds. The micro-structural investigation of the laser re-melted regions were carried out using Optical microscope, FESEM (Field Emission Scanning Electron Microscope) in back-scattered mode and TEM (Transmission Electron Microscope). The compositional evolution in the laser re-melted regions was carried out using EDS (Energy Dispersive Detector) attached to FESEM and TEM. The mechanical property of the re-melted regions was estimated using nano-indentation technique. The micro-structural examination showed that the laser re-melting of as-cast dendritic morphology leads to the development of < 200 nm Zr and Cu rich regions. The TEM-SAD analysis revealed the formation of amorphous Zr–Cu metallic glass in the laser re-melted regions. It was also observed that the fraction of Cu in the amorphous phase reduces with decrease in laser energy density which is attributed to enhanced solute trapping of Cu in β-Zr phase at higher scan speeds which was shown using Scheil solute trapping model of Thermocalc. The laser re-melted regions developed at high laser energy density shows superior values of nano-hardness and elastic modulus as compared to regions developed at lower laser energy density. This is attributed to higher concentration of Cu in Zr–Cu amorphous phase in laser re-melted regions developed at high laser energy density. [ABSTRACT FROM AUTHOR]

Static corrosion tests in LBE under oxygen-saturated and –depleted conditions at 500 °C for 1000 h were conducted to investigate the corrosion-induced diffusion layers on T91 and SS316L steels subject to dissolution and oxidation corrosion. Following nano-indentation experiments examined the variations of local mechanical properties within the corrosion layers. Under the present conditions, T91 steel showed better resistance to dissolution corrosion while higher susceptibility to oxidation corrosion against SS316L. For both steels, nano-indentation results showed a gradual decrease in mechanical properties from steel matrix to the corrosion side after dissolution corrosion. When subject to oxidation corrosion, the oxide scale formed on T91 steel showed lower Er-modulus and enhanced hardness in comparison with those of the steel matrix. An obvious decrease in both modulus and hardness was found at the interface between steel matrix and oxide scale.

Addressing the challenge of identifying an appropriate set of material and irradiation parameters for accurate simulation models using crystal plasticity finite element method (CPFEM), this study proposes a novel two-stage method for nano-indentation modeling of ion-irradiated face-centered cubic (FCC) materials. It includes implementing the strain-gradient crystal plasticity (SGCP) theory with irradiation effects and the calibration of simulation parameters using the particle swarm optimization (PSO) algorithm with experimental data. The proposed method consists of two stages: establishing CPFEM without irradiation effects in stage 1 and modeling irradiation effects based on CPFEM in stage 2. Modeling the nano-indentation test of ion-irradiated stainless steel 304 (SS304) using real experimental data is conducted to evaluate the efficiency of the proposed method. The accuracy of the calibration method using PSO is verified through comparisons between simulation and experimental results for force-indentation depth and hardness-indentation depth relationships under both unirradiated and irradiated conditions. Moreover, effect of ion-irradiation on the mechanical behavior during the nano-indentation of single crystal SS304 is also examined to demonstrate that the proposed method is a powerful approach for nano-indentation modeling of ion-irradiated FCC single crystals using SGCP theory and the PSO algorithm.

This paper aims to comprehensively evaluate the shear strength of various junctions between diamond chips and double copper bonded ceramic substrates. The study involves several stages, beginning with the deposition of Ti/Ni/Ag metallization system on diamond chips using a chemical vapor deposition (CVD) process. These metallization systems are selected to determine their suitability as ohmic contacts on diamond. In parallel, Ni/Au and Ni/Ag layers are electroplated onto the thick copper metallization of the ceramic substrate. Following these depositions, junctions are created for both Cu/Cu and C/Cu assemblies using different techniques: reflow process for AuGe solder joints, reflow-diffusion process for Ag-In joints, and a thermomechanical process for Ag nanoparticle joints. To assess the effectiveness of these techniques, the shear strength of the junctions is measured using a micro-shear test, which is analogous to a classical micro-scratching test. Additionally, the mechanical behaviors of the layers adjacent to the assemblies are analyzed through nano-indentation tests. Finally, the fracture surfaces are examined using scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) spectrometry to identify the microstructure and damage modes. The work described in the paper exhibits several innovative aspects. It introduces the novel combination of Ti/Ni/Ag metallization system on diamond chips, evaluated for its suitability as ohmic contacts, potentially leading to improved electrical and thermal performance in diamond substrate applications. The study employs diverse junction creation techniques, such as reflow for AuGe solder joints, reflow-diffusion for Ag-In joints, and a thermomechanical process for Ag nanoparticle joints, allowing for a thorough comparison and identification of the most effective method for different scenarios. We have also introduced an integrated testing methodology, which combines micro-shear tests and nano-indentation tests and provides a robust framework for assessing both the shear strength and mechanical properties of the junctions and adjacent layers, enhancing the reliability and depth of the evaluation. The specific focus on metallization system and junctions suitable for diamond, known for its exceptional thermal and electrical properties, positions this work as highly relevant for advanced electronic and thermal management applications.

As the flight speed of aircraft continues to increase, high-temperature wave-transparent materials for radomes or antenna windows face great challenges. The shortage of new high-performance wave-transparent materials is limiting the improvement of aircraft performance. In this work, dielectric and mechanical properties of RE 2 SiO 5 (RE = Ho, Er, Tm, Yb, and Lu) were investigated to explore their application as high-temperature wave-transparent materials. RE 2 SiO 5 (RE = Ho, Er, Tm, Yb, and Lu) ceramics possess relatively low dielectric constant and it is insensitive to the RE species. For the dielectric loss, they gradually decrease as the radius of rare earth ions decreases. In addition, RE 2 SiO 5 (RE = Ho, Er, Tm, Yb, and Lu) possesses good mechanical properties with high hardness and relatively low reduced modulus, and hardness is insensitive to the rare earth ion radii while the reduced modulus increases with the RE3+ ions radius decreases. They are larger than those of fused silica, the most used traditional high-temperature wave-transparent material. The results provide important material selection and optimization guidelines for RE 2 SiO 5 as the candidate for next-generation high-temperature wave-transparent materials. [ABSTRACT FROM AUTHOR]

Thin-film copper offers excellent film texture for multilevel interconnections in integrated circuit fabrication due to its superior resistance to electromigration and high electrical conductivity. To perform a chemical mechanical planarization process during semiconductor fabrication of copper, it is necessary to have a thorough understanding of the nanomechanical properties of thin-film copper. In this study, thin-film copper and reacted passivation layers on silicon substrate wafers are investigated for their nanomechanical properties under various environmental conditions. The results of this study indicate that thin-film copper passivation layers have different properties in deionized (DI) water and polishing slurry environments compared to thin-film copper exposed to ambient air. Interestingly, variations in temperature within wet environments do not significantly affect the properties of thin-film copper wafers; but changes in properties are largely driven by chemical processes. The insights gained from this study emphasize the significance of considering both the passivation layers and wet environments in semiconductor fabrication processes, which contributes to the advancement of copper-based interconnect materials and optimization of the chemical mechanical planarization process in semiconductor manufacturing. [ABSTRACT FROM AUTHOR]

Environmental barrier coatings (EBCs) are widely used to protect ceramic matrix composites (CMCs, SiCf/SiC, and Al2O3f/Al2O3), and they should have low thermal expansion coefficients (TECs) matching the CMCs and excellent mechanical properties to prolong their lifetime. Current EBC materials have disadvantages of phase transitions and insufficient mechanical properties, which affect their working temperatures and lifetime. It is necessary to develop new oxide EBCs. Ytterbium tantalate (YbTaO4) is a stable and novel EBC material, and we have improved the mechanical properties and TECs of Yb1−xAlxTaO4 (x = 0.05, 0.1, 0.2, 0.3, 0.4, 0.5) ceramics by replacing Yb with Al. XRD, SEM, and EDS are used to verify the crystal and microstructures, and nano-indentation is used to measure the modulus and hardness when changes in TECs are measured within a thermal expansion device. The results show that the phase structure of Yb1−xAlxTaO4 (x = 0.05, 0.1, 0.2, 0.3, 0.4, 0.5) is stable at 25–1400 °C within air atmosphere, and their high-temperature TECs (6.4–8.9 × 10−6 K−1, 1400 °C) are effectively regulated by introductions of different contents of Al, which enlarge their engineering applications for SiCf/SiC and Al2O3f/Al2O3 CMCs. The evolutions of TECs are analyzed from structural characteristics and phase compositions, and the increased TECs make Yb1−xAlxTaO4 potential EBCs for Al2O3 matrixes. Due to the high bonding strength of Al–O bonds, hardness, as well as Young's modulus, are enhanced with the increasing Al content, with Yb1−xAlxTaO4 (x = 0.05, 0.1, 0.2, 0.3, 0.4, 0.5) having a nano-hardness of 3.7–12.8 GPa and a Young's modulus of 100.9–236.6 GPa. The TECs of YbTaO4 are successfully regulated to expand their applications, and they match those of Al2O3 and SiC matrixes, as well as displaying improved mechanical properties. This work promotes applications of YbTaO4 as potential EBCs and provides a new way to regulate the TECs of tantalates. [ABSTRACT FROM AUTHOR]

This study employed nano-indentation technology, molecular dynamics simulation, and experimental investigation to examine the stress relaxation behaviour of a polycrystalline γ-TiAl alloy. The simulation enabled the generation of a load-time curve, the visualisation of internal defect evolution, and the mapping of stress distribution across each grain during the stress relaxation stage. The findings indicate that the load remains stable following an initial decline, thereby elucidating the underlying mechanism of load change during stress relaxation. Furthermore, a nano-indentation test was conducted on the alloy, providing insight into the load variation and stress relaxation behaviour under different loading conditions. By comparing the simulation and experimental results, this study aims to guide the theoretical research and practical application of γ-TiAl alloys. [ABSTRACT FROM AUTHOR]

The microstructural, tribological, and mechanical performance of friction-stir welded AA6061-T6 and AZ31 alloys were investigated using electron back scattered diffraction, scanning electron microscope, X-ray diffraction, and electron dispersed spectroscopy methods. The non-destructive X-ray microcomputed tomography test was used to analyse weld porosity. The distribution of volumetric and surface flaws (pores) was found to be confined across the weldment. Using a novel atomic force microscopy method, the nano-tribological characteristics of the base metal and localized regions of welded sample were studied for the first time. The significant difference in wear and friction behaviour was observed in all weld zones and base metal of magnesium side, which was correlated with the hardness of these regions. AFM results showed strong variation in tribological properties in correlation with the hardness trends of different weld zones, i.e. higher hardness leads to low wear. In weldments, intermetallic compounds such as Al12Mg17 and Al3Mg2 were produced, resulting in nanohardness differences as measured by the nanoindentation test. The joint efficiency of 65%, 84%, and 91% were obtained at welding speeds of 16 mm/min, 20 mm/min, and 25 mm/min, respectively. [ABSTRACT FROM AUTHOR]

In this investigation, 0.19–1.8 wt.% of Ge was introduced into a ternary Zn-Mg-Al alloy. The introduction of Ge had a significant impact on the microstructure, leading to the formation of Mg2Ge. The area fraction of the eutectic phase diminished with increasing Ge additions. Small-scale test techniques were utilised to evaluate the mechanical properties due to the changes in microstructure. Zn-Mg-Al alloys were found to be inherently harder compared to standard hot-dip Zn-containing 0.2 wt.% Al. The hardness and strength of the Zn-Mg-Al alloys decreased with the increase in Ge additions. [ABSTRACT FROM AUTHOR]

Extracting mechanical data of thin films on rigid substrates using nanoindentation is compromised by the mechanical properties of underlying substrates, which may falsify the obtained results. With ongoing miniaturization, the substrate influence becomes more pronounced. In this study we present an experimental approach to extract the true Youngs modulus of crystalline-amorphous multilayers by means of nanoindentation. We used 1 µm thick multilayers comprised of amorphous CuZr and nanocrystalline Cu. All films were deposited onto two rigid substrate types with Youngs moduli below and above the ones expected for the deposits (film-to-substrate hardness and elastic moduli ratios between 0.3 to 1.1 and 0.6 to 1.5, respectively). Linear extrapolation of indentation data to zero indentation depth allows to precisely determine the real films Youngs modulus. Same investigations were performed on monolithic Cu and CuZr films of same thickness. While the hardness values change with the variation of the bilayer thickness of the multilayer structures, the Youngs modulus is not affected by the interfaces.

Modified layers with refined and homogenized microstructure were obtained on a cast manganese aluminum bronze (MAB) by friction stir processing (FSP) and laser surface melting (LSM). In 3.5% NaCl solution, a much more protective film was formed and uniform corrosion occurred for the two surface-modified MABs. The corrosion rate of the cast sample was reduced by a factor of 29.73% after FSP and 51.35% after LSM. The cavitation erosion (CE) rate of the cast MAB was about 1.83 and 3.07 times larger than that of the FSP and LSM samples, respectively. The CE resistance increment was highly attributed to the improved hardness and enhanced nano-indentation behavior after FSP or LSM. For each MAB, the CE resistance decreased with extended pre-immersion time. Compared with the result of the correspondingly freshly-prepared sample, the CE rate was raised by a factor of 36.22%, 42.97% and 44.00% after 30 days’ pre-immersion for the cast, FSP and LSM MABs, respectively. For the cast and FSP MABs, mechanical impact was the leading factor accounting for CE degradation. For the pre-corroded samples, corrosion damage at the β and κ phases weakened the mechanical properties and thus triggered more grievous material exfoliation under CE. For the LSM MAB, CE-corrosion synergy dominantly gave rise to the CE damage. Corrosion at grain boundaries after pre-immersion also deteriorated the CE performance. The LSM MAB possessed the highest corrosion and CE resistances because the fine single-phase microstructure reduced the galvanic corrosion effect and crack propagation tendency under CE impact.

Nix–Gao's factor (81/2) was replaced with (4.5Ct2) using variable constraint factor (Ct) for size-dependent analysis of crystalline coatings. Experimental investigations on annealed NiB coating (5 wt% boron) aimed at defense applications involved twelve Berkovich nanoindentation tests (displacements: 500, 1000, and 1500 nm; strain rates: 0.05, 0.1, 0.15, and 0.20 s−1). SEM and XRD analyzed cauliflower-type surface morphology and crystallinity. NiB coatings exhibited Intrinsic hardness (H0) of 9.65 ± 0.26 GPa, material characteristic length (h*) of 194.8 ± 10 nm, and elastic modulus (E) of 264 ± 10 GPa. Indentation size effects of these coatings attributed to increased geometrically necessary dislocation density. [ABSTRACT FROM AUTHOR]

In the present investigation, continuous stiffness measurement (CSM) using nano-indentation technique has been employed to measure the hardness and strain rate sensitivity (SRS) parameter of Ti-6Al-2Mo-4Zr-2Sn (AM-Ti6242) alloy. The measured properties have been subjected to exploratory data analysis and interpreted based on local microstructure, composition and micro-texture. Very interestingly, the chemically homogeneous microstructure showed mechanical heterogeneity. The presence of the martensite phase and formation of the stress-induced nano-twins in the AM Ti6242 have been found to influence its nano-mechanical behaviour in a completely different way compared to the non-additively manufactured Ti6242. [ABSTRACT FROM AUTHOR]

Stainless steel 316L is commonly used in biomedical applications like dental implants, surgical tools, and other devices due to its corrosion resistance and cost-effective materials compared to other biomaterials. It must be enhanced since 316L SS has a relatively low hardness and wear resistance. The coating process includes applying functional materials to the surface to modify and give it the desired properties. This study used a PVD technique for coating diamond-like carbon (DLC) on the surface of 316L stainless steel to enhance its material surface properties. The coated and uncoated SS316 surfaces were exposed to nanoindentation (ultra-nano hardness tester (UNHT3) and electrochemical corrosion tests such as open circuit potential, potentiodynamic polarization, and electrochemical impedance spectroscopy in simulated body fluids at 37 °C. SEM characterized the morphologies and compositions of the surfaces with energy-dispersive X-ray spectroscopy. [ABSTRACT FROM AUTHOR]

Mg/Al clad plate was prepared by a combined process of corrugated roll rolling, flat roll rolling and annealing. The results show that the grain refinement is obvious in the first corrugated roll rolling, the grain grows before the second pass annealing, and the grain refines again after the second pass flat roll. By increasing the annealing temperature, the grain growth is promoted, the hardness of Mg17Al12 compound layer is 1.378–2.812 GPa, and that of Al3Mg2 compound layer is 1.161–1.281 GPa, which is higher than that of base metal. The mechanical properties of clad plate in transverse direction (TD) are better than those in rolling direction (RD). The residual stress can be eliminated by annealing, and the mechanical properties of clad plate can be improved. [ABSTRACT FROM AUTHOR]

The research and development of chrome-free refractories for non-ferrous metal smelting furnace is imperious for environmental protection. In present investigation, the magnesia-zirconia composite refractories were fabricated with sintered magnesia and desilicated zirconia as raw materials. The mechanical properties, thermal shock resistance properties, phase and microstructure of samples were investigated, and the specific fracture energy of magnesia-zirconia refractories matrix was obtained by statistical grid nanoindentation. The results showed that the magnesia-zirconia refractories added 5 wt%(MZ1 sample) desilication zirconia obtained the best performance, where the apparent porosity was only 18.06 % and the CMOR was 14.9 MPa. In addition, the specific fracture energy of MZ1 sample was 248 N m−1, which was 98 % higher than MZ0 (125 N m−1). Compared with the sample without desilicated zirconia, the residual strength ratio of magnesia-zirconia refractories increased more than 50.0 %. The improvement of the thermal shock resistance and mechanical properties of magnesia refractories was greatly attributed to the formation of t-ZrO 2 in the matrix, where the dissolve of Ca2+ into the ZrO 2 in the matrix is more benefit to the formation of the stable t-ZrO 2 phase. The propagation of cracks is prevented by t-ZrO 2 , which further prevent the trans -granular fracture of magnesia aggregate. Therefore, the magnesia-zirconia refractories contained t-ZrO 2 was expected to be candidate materials as chromium-free refractories used in non-ferrous metal smelting furnaces. [ABSTRACT FROM AUTHOR]

Evaluate the ability of strontium fluoride on bond strength and enamel integrity after incorporation within orthodontic adhesive system as a delivery vehicle. Experimental orthodontic adhesive system Transbond™ XT were modified with 1% Sr2+, 0.5% SrF 2 , 1% strontium, 0.5% Sr2+, 1% F-, 0.5% F-, and no additions were control. Mixing of formulation was monitored using Fourier transform infrared spectroscopy. Small-molecule drug-discovery suite was used to gain insights into Sr2+, F-, and SrF 2 binding. Shear bond testing was performed after 6-months of ageing. Enamel blocks were cut, and STEM pictures were recorded. Specimens were indented to evaluate elastic modulus. Raman microscope was used to collect Raman spectra and inspected using a scanning electron microscope. Crystal structural analysis was performed using X-ray diffraction. Effect of material on cellular proliferation was determined. Confocal was performed to evaluate the effect of formulation on biofilms. FTIR of modified adhesives depicted peak changes within range due to various functional groups existing within samples. TEM represented structurally optimized hexagonal unit-cell of hydroxyapatite. Mean shear bond strength is recorded highest for Transbond XT with 1% SrF2. Dead bacterial percentage appeared higher in 0.5% SrF 2 and 1% F- specimens. Crystal lengths showed an increase in 0.5% and 1% SrF 2 specimens. Phase contrast within TEM images showed a union of 0.5% SrF 2 crystal with enamel crystal with higher elastic modulus and highly mineralized crystalline hydroxyapatite. Intensity of ν1 PO 4 3- and ν1 CO 3 2- along with carbonate - / ν1PO 4 3- ratio displayed good association with strontium fluoride. The formulation showed acceptable cell biocompatibility (p < 0.353). All specimens displayed characteristic diffraction maxima of different apatite angles within XRD. Experimental results suggested good biocompatibility, adequate mechanical strength, and far-ranging crystallization ability. This would provide a new strategy to overcome the two major challenges of fixed orthodontics, biofilm growth, and demineralization of enamel. [ABSTRACT FROM AUTHOR]

In this study, we focused on depositing a target material, cobalt-iron-dysprosium (Co60Fe20Dy20), onto silicon (Si) (100) substrates with thickness varying from 10 nm to 50 nm through a direct-current (DC) magnetron sputtering technique. The subsequent step involved subjecting the samples to an hour-long annealing process in a vacuum annealing furnace at temperatures of 100°C, 200°C, and 300°C. To assess the elemental composition of the CoFeDy films, energy-dispersive X-ray spectroscopy (EDS) was employed. An observed trend indicated an increase in low-frequency alternating-current magnetic susceptibility (χac) with the increasing thickness. Remarkably, the CoFeDy films exhibited their peak χac following annealing at 300°C, with an optimal resonance frequency of 50 Hz. After annealing at 300°C, the CoFeDy film's surface energy peaked at 50 nm. The magnetic, electrical, and adhesive properties of the CoFeDy films were notably influenced by surface roughness at different annealing temperatures. Atomic force microscopy (AFM) analysis revealed a gradual reduction in film roughness post-annealing, corresponding to smoother surfaces indicative of a weaker domain wall pinning effect, heightened carrier conductivity, and increased liquid spreading. Collectively, these outcomes contributed to diminished χac, reduced electrical resistance, and enhanced adhesion. [ABSTRACT FROM AUTHOR]

To explore the effect of weld geometry on irradiation-induced segregation and irradiation hardening, three different groove types of 316L austenitic stainless steel welds were studied in H+ with 5-MeV to a dose of 6.2 × 1017 ions/cm2 at 400 °C by means of Grazing incident X-ray diffraction, transmission electron microscope, energy-dispersive X-ray spectroscopy and nano-indentation technology. The results show that there was no new phase in three weld geometries after ion irradiation. A smaller heat input made the grain structure of the double U-groove weld smaller, and the surface void size was the smallest after irradiation. The higher grain density and grain boundary density made solute atoms more uniform and less segregated during diffusion, so that the weld had better mechanical properties. It is a feasible idea and method to refine the weld grain by double U-groove welding, so as to improve the irradiation-induced segregation resistance of the weld. [ABSTRACT FROM AUTHOR]

Ti2AlN MAX phase films produced at different N2 flow rates and different annealing temperatures were deposited on 52100 steel substrates using the closed-field unbalanced magnetron sputtering technique. N2 flow rates were changed to 2, 3.5, and 5 sccm. Due to the increasing N2 flow rate, film thickness decreased from 2 to 1.3 µm. Then the produced films were subjected to annealing at temperatures of 700, 750, and 800°C. After the film produced at a flow rate of 2 sccm was annealed at 750°C, the presence of the Ti2AlN MAX phase was determined. The binding energies of Ti 2p, Al 2p, and N 1s determined in the XPS analysis confirmed the existence of the Ti2AlN film. The friction coefficient measured for Ti2AlN MAX phase films was calculated as 0.53, the hardness value as 22.8 GPa, the elastic modulus as 291.4 GPa, and the wear rate as 2.96 × 10−4 mm3/(N·m). [ABSTRACT FROM AUTHOR]

With the continuous drive of the aerospace industry to implement additive manufactured (AM) components into the next generation of aero-engines, to benefit from the near net shape and weight saving potential that the technology has to offer, the requirement to understand their mechanical performance is also rising in parallel. This is further complicated by the highly localised and transient micro/macro structures that AM produced parts typically possess, raising a question mark over the suitability of more traditional mechanical test approaches where the bulk properties are heavily influenced by the presence of a single defect. As such, alternative experimental approaches, capable of establishing the properties of smaller more intricate structures and geometrically representative microstructures and cross sections, needs to be considered for process parameter down-selection. This paper will explore the suitability of several alternative mechanical test methodologies in characterising the mechanical behaviour of a nickel based superalloy, Inconel 718 (IN718), produced by laser powder bed fusion (LPBF), and establish which results correlate most favourably to those generated through more conventional means. For the first time, results will be presented from several mechanical test methodologies including small punch, shear punch, hardness, nano-indentation and profilometry based indentation plastometry experiments; a set of mechanical test approaches that have yet to be directly compared and discussed in a single study on an additively manufactured material. Findings will be supported by advanced microscopy in the form of field emission SEM and crystallographic texture maps produced through electron back-scattered diffraction.

Abstract: A method for small-scale testing and imaging of freestanding, microtomed polymer films using a push-to-pull device is presented. Central to this method was the development of a sample preparation technique which utilized solvents at cryogenic temperatures to transfer and deposit delicate thin films onto the microfabricated push-to-pull devices. The preparation of focused ion beam (FIB)-milled tensile specimens enabled quantitative in situ TEM tensile testing, but artifacts associated with ion and electron beam irradiation motivated the development of a FIB-free specimen preparation method. The FIB-free method was enabled by the design and fabrication of oversized strain-locking push-to-pull devices. An adaptation for push-to-pull devices to be compatible with an instrumented nanoindenter expanded the testing capabilities to include in situ heating. These innovations provided quantitative mechanical testing, postmortem TEM imaging, and the ability to measure the glass transition temperature, via dynamic mechanical analysis, of freestanding polymer films. Results for each of these mentioned characterization methods are presented and discussed in terms of polymer nanomechanics. Graphic Abstract: [Figure not available: see fulltext.]

Abstract: A method for small-scale testing and imaging of freestanding, microtomed polymer films using a push-to-pull device is presented. Central to this method was the development of a sample preparation technique which utilized solvents at cryogenic temperatures to transfer and deposit delicate thin films onto the microfabricated push-to-pull devices. The preparation of focused ion beam (FIB)-milled tensile specimens enabled quantitative in situ TEM tensile testing, but artifacts associated with ion and electron beam irradiation motivated the development of a FIB-free specimen preparation method. The FIB-free method was enabled by the design and fabrication of oversized strain-locking push-to-pull devices. An adaptation for push-to-pull devices to be compatible with an instrumented nanoindenter expanded the testing capabilities to include in situ heating. These innovations provided quantitative mechanical testing, postmortem TEM imaging, and the ability to measure the glass transition temperature, via dynamic mechanical analysis, of freestanding polymer films. Results for each of these mentioned characterization methods are presented and discussed in terms of polymer nanomechanics. Graphic Abstract: [Figure not available: see fulltext.]

This study employed nano-indentation technology, molecular dynamics simulation, and experimental investigation to examine the stress relaxation behaviour of a polycrystalline γ-TiAl alloy. The simulation enabled the generation of a load-time curve, the visualisation of internal defect evolution, and the mapping of stress distribution across each grain during the stress relaxation stage. The findings indicate that the load remains stable following an initial decline, thereby elucidating the underlying mechanism of load change during stress relaxation. Furthermore, a nano-indentation test was conducted on the alloy, providing insight into the load variation and stress relaxation behaviour under different loading conditions. By comparing the simulation and experimental results, this study aims to guide the theoretical research and practical application of γ-TiAl alloys.