Journal of Materials Science最新文献

High-entropy alloys (HEAs) favor solid solution phases and exhibit superior properties in irradiation environments. However, the radiological risks of Co necessitate Co-free designs. In this work, different data augmentation techniques, i.e., synthetic minority oversampling technique (SMOTE) and Wasserstein generative adversarial network (WGAN) with gradient penalty, are evaluated for predicting body-centered cubic (BCC) phase stability in Co-free HEAs. Principal component analysis (PCA) reduces dimensionality. A simple multilayer perceptron trained on these augmented datasets achieved cross-validation accuracies of 84.39% (SMOTE) and 86.82% (WGAN). Shapley additive explanations (SHAPs) and PCA analyses show valence electron concentration’s dominance of SMOTE-generated data per Hume-Rothery rules. WGAN-generated data offer balanced thermodynamic contributions for enhanced generalizability. These results show that for predicting phases in materials with small datasets, simple algorithm supported by data augmentation techniques can be as effective as complex algorithms. This work can guide HEA design for niche-subset applications and broaden the utility of machine learning for small datasets.

Austenitic stainless steel is highly susceptible to solidification cracking during welding, which seriously affects the quality and safety of austenitic stainless steel welded joints. Solidification cracks mainly appear in the mushy zone behind the molten pool at the end of solidification during welding. The factors influencing solidification cracks mainly come from metallurgy and mechanics. This paper summarized and reviewed the formation mechanism of solidification cracks during welding austenitic stainless steel. The models of solidification crack and criteria for evaluating the susceptibility of austenitic stainless steel was also reviewed in detail. In addition, the research progress in the crack susceptibility test methods, controlling factors and strategies of austenitic stainless steel was also analyzed. The future research direction in this significant topic was also proposed. Enhanced understanding of solidification cracking phenomena offers an opportunity to improve cracking resistance and high-quality welding of austenitic stainless steels.

Cu–Cr–O delafossite thin films were grown by metal–organic chemical vapor deposition with various extrinsic dopants (Al, Mg, Mn, Sc, Y, and Zn) targeted at 5 at% to investigate how such doping influences their structure and properties. X-ray photoelectron spectroscopy revealed that the actual dopant incorporation is well below the nominal 5%, with only Al and Sc present above quantification limit. An off-stoichiometric CuCrO_2+0.15 composition is determined, with no secondary phases detected. Transmission electron microscopy indicates that films grown on c-plane sapphire are epitaxial near the substrate interface but relax into a polycrystalline structure beyond 20–30 nm, while films on silicon are polycrystalline throughout. All films show high p-type conductivity (on the order of 10–10² S cm⁻¹) attributable to the excess oxygen, with no significant variation among different dopants. Optical transmission measurements indicate a slight red-shift (~ 20 nm) of the absorption edge for all doped films, likely arising from strain effects and subtle structural disorder introduced during growth. We discuss the influence of lattice strain (sin²ψ measurements showing residual strain) and small-polaron absorption behavior in these films. Despite limited incorporation of dopants, subtle structural and optical shifts suggest that dopant precursor chemistry and growth conditions play a significant role in influencing film stoichiometry and properties.

This work presents an experimental investigation of the temperature dependence of spectral and total emissivity of microstructured highly doped silicon, a class of black silicon (BSi) surfaces, which behaves as an ultra-broadband and ultra-black behavior, nearly a perfect blackbody up to a wavelength of 10 µm. We make a comparison with a flat surface of similar silicon taken as a reference. Direct infrared (IR) emissivity measurements were performed under normal incidence across 2–20 μm spectral range and at temperatures between 100 and 350 °C, using a newly developed experimental setup. While previous studies have demonstrated the excellent absorptivity of BSi at room temperature, our results confirm that BSi maintains near-unity emissivity up to a wavelength of 10 μm even at high temperatures. Notably, the total hemispherical emissivity is found to increase slightly from ~ 0.95 at 150 °C up to ~ 0.98 at 350 °C. These values significantly exceed by far those of the flat Si reference samples. The results are further compared with absorptivity measurements at room temperature obtained from FTIR spectroscopy and with literature data. This study provides a comprehensive temperature resolved and spectrally resolved emissivity properties for highly doped BSi, establishing its suitability for advanced thermal applications such as thermophotovoltaic emitters, thermal infrared light sources, and radiative cooling.

The rapid development of science and technology has led to the aggravation and complexity of electromagnetic radiation pollution. Therefore, multifunctional electromagnetic interference shielding materials have become increasingly indispensable. Based on the advantages of textile materials, the modular coupling assembly strategy was utilized to achieve the structural regulation of the multifunctional PP conductive composite film and effectively endowed it with excellent EMI shielding performance. In this study, the adhesive property of polydopamine was utilized to enhance the chemical reactivity of PP films. The construction of porous conductive structures and core–shell conductive structures of PPy inside and outside PP fibers was achieved by controlling the polymerization rate of pyrrole in a low-temperature environment. The macroscopic encapsulation of the hydrophobic layer enhanced the bonding strength between the PP substrate and the conductive layer. The results show that different concentrations of pyrrole affected the microstructure and EMI shielding performance. When the concentration of pyrrole was 0.8 mol/L, the surface contact angle and surface resistance of the PP composite film were 138.42° and 73 Ω, respectively. In addition, the shielding value of the PP composite film was as high as 28.02 dB, which could effectively shield 99.84% of electromagnetic waves. This preparation strategy of coupling multiple functional layers to realize multifunctional composite films provides research ideas for the structural design of multi-purpose smart wearable electromagnetic protection composite materials.

Dielectric energy storage capacitors, as core components of pulse power devices, hold significant strategic importance in cutting-edge technological fields such as high-power pulse systems. Lead-based antiferroelectric ceramics have emerged as highly promising candidate materials due to their prominent energy storage density. However, such ceramics exhibit pronounced polarization hysteresis during the antiferroelectric-ferroelectric phase transition, thereby leading to low energy storage efficiency. Furthermore, during pulse charge-discharge cycling, critical issues including inadequate thermal stability and short fatigue life become apparent, severely restricting their practical applications. To address these issues, relaxor antiferroelectric Pb_0.91La_0.06(Zr_1 − xTi_x)O₃ (PLZT_x) ceramics were synthesized via precise composition design. This study found that when the orthorhombic (O) and pseudo-cubic (P_C) phases coexisted, a minor P_C phase could lower the antiferroelectric-ferroelectric phase transition barrier, thus enhancing the antiferroelectricity and relaxation of PLZT-based ceramics and significantly optimizing their energy storage performance. Additionally, the presence of the P_C phase suppresses lattice distortion, improves structural symmetry, and thereby enhances the thermal stability during pulse charge-discharge cycles. This work establishes a clear correlation between “local structure–macroscopic property”, revealing the critical role of the P_C phase in optimizing the electrical properties of orthorhombic antiferroelectric ceramics and providing theoretical guidance for the design of high-performance antiferroelectric ceramics.

The application of magnesium alloys is restricted by the challenge of enhancing strength and ductility simultaneously. In this work, a corrugated rolling strategy combined with subsequent annealing is adopted to overcome this limitation in AZ31 magnesium alloy. Strain distribution was quantified using digital image correlation (DIC), while microstructural features were characterized by electron backscatter diffraction. DIC results show that, before annealing, deformation initiates in the trough and lower transition zones, accompanied by pronounced localized strain on the corrugated side. After annealing, deformation begins in the upper transition and trough zones, where localized strain also concentrates on the corrugated side, and the elongation increases by 197%. Microstructural analysis indicates that static recrystallization refines grains and eliminates shear bands, improving crack propagation resistance and mitigating stress concentration. The corrugated side and middle layer exhibit higher average KAM values, while the flat side shows a lower proportion of basal slip systems with high Schmid factors and a higher proportion of low-angle misorientations. Consequently, during tensile loading, the corrugated side and middle layer deform first and develop localized strain, whereas the flat side deforms more uniformly. Overall, annealing improves the strain distribution of corrugation-rolled sheets, eliminates shear bands, and adjusts misorientation angle. It also promotes the formation of a millimeter-scale embedded structure, which markedly enhances the ductility of the material. The combined process of corrugation rolling followed by annealing enables a simultaneous increase in both strength and ductility.

To address key challenges at metal-ceramic/steel heterogeneous interfaces, specifically microcracking from thermal expansion mismatch, weak interfacial bonding, and brittle phase formation, this study introduces an innovative hybrid process combining mechanical alloying with multi-pass hot rolling. This study systematically examines how Ni additions influence interfacial evolution and mechanical properties in TiB₂-reinforced high-strength steel. Integrated thermodynamic modeling, XRD phase analysis, and SEM–EDS characterization reveal Ni′s pivotal role in redirecting interfacial reaction pathways. While the TiB₂–Fe system generates brittle Fe₂B phases during processing, the TiB₂–Ni system promotes Ni₃B intermetallic formation, effectively suppressing detrimental brittle compounds. With 66 wt.% Ni content, the interface develops a continuous gradient transition layer measuring 8–15 μm in thickness, demonstrating significantly enhanced elemental interdiffusion and structural continuity compared to the 50 wt.% Ni system. Microhardness profiles further verify superior interfacial hardness distribution and bonding integrity in the TiB₂–66 wt.% Ni composite. By establishing correlations between phase evolution and interfacial microstructure, this work elucidates the fundamental mechanism through which Ni content enhances interfacial strength and toughness, providing innovative design principles and processing strategies to overcome bonding challenges in ceramic-metal systems.

Layered indium monoselenide (InSe) semiconductors have attracted extensive attention due to their promising applications in spectroscopy, thin-film electronics, and optoelectronic devices. The crystallographic polytypic nature of InSe facilitates diverse phase transitions, which, however, may compromise its exceptional performance under fluctuating environmental conditions. In this study, we synthesized high-quality β-InSe single crystals and systematically examined the evolution of phonon modes and polarization anisotropy over a temperature range of 80–400 K and under hydrostatic pressures up to 13.2 GPa using nondestructive Raman spectroscopy. The Raman spectra reveal two distinct out-of-plane A₁(({Gamma }_{1}^{2})) and A₁(({Gamma }_{1}^{3})) modes, accompanied by an in-plane vibrational mode. The continuous Raman redshift observed upon heating is primarily attributed to intrinsic phonon–phonon anharmonicity, with cubic anharmonicity significantly dominating over quartic anharmonicity. Under hydrostatic pressure, consistent blueshifts were captured in all Raman-active phonon modes, driven by bond length contraction and increased vibrational energy. Notably, the applied pressure does not alter the material’s fourfold symmetry or polarization angles on the edge plane, owing to strong interlayer cohesion during slip. No spectral anomalies were detected within the investigated temperature and pressure ranges, highlighting the remarkable structural integrity of β-InSe. This research provides insights into the stable spectral performance of layered semiconductors, laying a foundation for their application in dynamic external environments.