Advanced Engineering Materials最新文献

This study systematically investigates the influence of extrusion temperature (200, 250, and 300 °C) on the microstructural evolution, mechanical properties, and tribological behavior of a ZK60 magnesium alloy processed by an extrusion-shear (ES) technique. Through comprehensive characterization methods including scanning electron microscopy /electron backscatter diffraction, room-temperature tensile/compression tests, hardness measurements, and rotary wear tests, the critical role of temperature in governing dynamic recrystallization (DRX) mechanisms, texture development, fracture modes, and wear mechanisms is elucidated. The results indicate that increasing the extrusion temperature leads to grain coarsening and a nonmonotonic variation in basal texture intensity, which peaks at 250 °C. The ES processing at 200 °C promotes continuous DRX, resulting in a homogeneous fine-grained microstructure that yields an optimal combination of mechanical strength and wear resistance. At 250 °C, the dominance of dynamic recovery leads to significant texture strengthening but a consequent degradation in ductility and wear performance. At 300 °C, the activation of discontinuous DRX alongside grain coarsening results in microstructural heterogeneity and inferior properties. This work provides fundamental insights and practical guidelines for optimizing the ES process parameters of ZK60 alloy for enhanced performance under demanding service conditions.

Titanium matrix composites (TMCs) can be used in some important industrial fields, and they are easy to generate the defects during loading. It is significant to modify the microstructure and repair the defects. In this article, the microstructure of secondary α (α_s) phase precipitated from the β phase via electroshock treatment (EST) in TiB/Ti-6Al-4V. The orientation of α phase and TiB varied, the maximum texture intensity of α phase decreased, and the orientation became more uniform. The maximum texture intensity of TiB increased. After EST, the yield strength of TiB/Ti-6Al-4V increased by 1345.7 MPa, the compressive fracture strain is 20.5%, and the hardness value is 420.4 HV. During the process of fatigue failure, the tips of TiB are easy to form micropores and defects. However, the fatigue defects can be repaired by EST, and the volume rate of repairing defects reached 73.94%–82.17%. All results indicate EST is an efficient method to repair defects and improve mechanical properties of TMCs.

Based on metastable engineering and valence electron concentration design, three (Ni_12–x–yCo_xFe_yAl₂Ti₂)_97.5B_2.5 (x = 4, y = 2; x = 3.5, y = 1.5; x = 3, y = 1) complex component intermetallic alloys (CCIMAs) are prepared by adjusting Co and Fe contents. Through multiscale characterization and mechanical testing, the effects of Co/Fe alloying degree on microstructural evolution, solidification path, and mechanical behavior are systematically investigated. The results show that the synergistic addition of Co/Fe shifts the eutectic point toward the Ni-rich side, significantly expanding the formation range of the B2 phase. This promotes the precipitation of B2 primary dendrites, with its volume fraction and size increasing notably as the alloying degree rises. Mechanical tests indicate that the hardness and compressive yield strength of the alloys improve with the addition of Co/Fe. The optimized composition (Ni₇Co_3.5Fe_1.5Al₂Ti₂)_97.5B_2.5 exhibits a compressive yield strength of 1066 MPa and a fracture strain of 53% while retaining ≈450 MPa yield strength at 950 °C. This work elucidates the mechanism by which Co/Fe alloying regulates the dual-phase microstructure by altering the eutectic reaction pathway, thereby achieving performance optimization. It provides guidance for designing novel high-performance CCIMAs, facilitating the attainment of desired microstructures and improved performance.

Triboelectric nanogenerators (TENGs) emerge as efficient energy-harvesting devices that convert mechanical energy into electricity. While various dielectric materials have been explored, the potential of torrefied biowaste materials as dielectric layers remains underexplored. This study investigates the triboelectric performance of three unique biowaste materials—torrefied pine sawdust (P.S.), chicken manure (C.M.), and rose pulp (R.P.)—embedded in silicone matrices at varying weight fractions (2.5–10%). The study employs comprehensive material characterization techniques, including scanning electron microscope imaging and electrical performance analysis, to evaluate charge accumulation, dielectric properties, and power generation efficiency. The results reveal that the optimal embedding ratio is 7.5 wt% for P.S. and C.M., yielding maximum power outputs of 184 and 222 mW, respectively, at 1 MΩ load resistance. In contrast, R.P. exhibits peak performance at 2.5 wt%, generating 176 mW. The highest open-circuit voltage values are recorded as 1250 V for P.S., 1400 V for C.M., and 1325 V for R.P. at 50 MΩ resistance. The findings highlight that torrefied C.M. provides superior charge retention and power stability, outperforming P.S. and R.P. The study bridges a critical research gap by demonstrating the feasibility of torrefied biowaste as an eco-friendly alternative for enhancing TENG efficiency.

Lithium–metal anodes present significant potential for the advancement of next-generation high-energy-density batteries. Nevertheless, their route to commercialization is obstructed by enduring challenges, such as dendrite growth, unstable solid-electrolyte interphases (SEIs), and pronounced volume variations. Traditional approaches, including the use of electrolyte additives and artificial SEIs, typically tackle these problems in a piecemeal manner, lacking the ability to integrate interfacial, mechanical, and kinetic stability concerns. This review reconceptualizes lithium alloying strategies as multifunctional systems that incorporate secondary metals (e.g., Mg, Ag, Sb) into lithium matrices, facilitating simultaneous improvements in nucleation consistency, dendrite inhibition, and strain alleviation. Distinct from prior works, three original frameworks are pioneered: 1) phase diagram-guided alloy design to correlate thermodynamic stability with electrochemical stressors; 2) defect engineering paradigms linking lattice defects to ion transport and stress redistribution; and 3) interfacial charge redistribution at lithium-alloy boundaries to govern the nucleation and growth processes of lithium deposits. The review methodically analyzes alloying strategies from the perspectives of atomic mechanisms, material innovations, and system-level integration. By synthesizing multiscale design principles, this work transitions the focus from empirical methods to strategically engineered lithium–metal batteries, aiding their evolution from laboratory settings to the global energy storage arena.

Thermomechanical Metamaterials

The diode-engineered heat regulation pipe features a concentric structure with radial thermal diode units around a central water channel. In insulation mode (left), the diodes block heat loss in low temperatures; in absorption mode (right), they harvest external heat in high temperatures. This bidirectional design enables precise, energy-efficient thermal management of fluid transport. More information can be found in the Research Article by Jaehyung Ju and co-workers (10.1002/adem.202501280).

Composite Metal Foam

Entrapped air inside the airtight porosities of composite metal foam provides lightweightness and cushion-ability. This could boost the safety of a tank car upon impact, thereby protecting the environment from HAZMAT spillage and fire. More information about the results of both experimental and numerical approaches can be found in the Research Article by Afsaneh Rabiei and Aman Kaushik (10.1002/adem.202501605).

In this article, the extruded Mg-3Nd-1Gd-1Zn-0.5Zr alloy is systematically investigated to elucidate its thermal deformation behavior, microstructural evolution, and dynamic recrystallization (DRX) mechanisms. High-temperature experiments are conducted on a CMT high-temperature tensile testing machine at temperatures ranging from 523 to 673 K and strain rates of 0.0001–0.1 s⁻¹. An Arrhenius-type constitutive equation is developed from stress–strain curves, and processing maps are generated. The results show that deformation parameters strongly affect the high-temperature plastic response. The alloy exhibits rheological instability at high strain rates, while favorable formability occurs only within a narrow temperature interval. Increasing temperature and decreasing strain rate enhances the power dissipation coefficient and suppress instability, defining the optimal hot-working domain as 640–670 K and 0.0001–0.001 s⁻¹. Within this domain, CDRX (continuous DRX) occurs through subgrain boundary migration, forming uniform equiaxed grains and reducing dislocation density, also improving workability and stabilizing flow. At high temperatures and low strain rates, the fraction of recrystallized grains increases, dislocation density decreases, and rheological stress declines, promoting homogeneous microstructures. Microstructure analysis reveals that CDRX predominates at 673 K/0.001 s⁻¹, while discontinuous DRX dominates at 623 K/0.1 s⁻¹. These findings establish a direct link between processing conditions, DRX mechanisms, and macroscopic deformation behavior.

Dual-Material Deformable Units

In their Research Article (10.1002/adem.202501200), Zhutong Li, Xiang Peng, and co-workers investigate modular and programmable deformable structures based on the rigid-flexible combination of PLA and TPU. Results show that leveraging the modular and parametric design advantages of multi-material structures enables deformation modes such as expansion, bending, and torsion, and provides the capability for multi-modal coordinated deformation.

High entropy alloys (HEAs) are a new class of metals that exhibit unique mechanical performance. Among HEAs, additively manufactured eutectic high entropy alloys (AM EHEAs) have recently emerged as candidate materials for use in extreme conditions due to their simultaneous high strength and ductility. However, the deformation and structural evolution of AM EHEAs under conditions of high pressure have not been well characterized, limiting their use in extreme applications. Dynamic compression experiments and molecular dynamics simulations are presented to study the structural evolution of AM EHEA AlCoCrFeNi_2.1 when compressed to pressures up to 400 GPa. In situ X-ray diffraction measurements capture the appearance of face-centered cubic and body-centered cubic phases at different pressure conditions, with pure- and mixed-phase regions. Understanding the phase stability and structural evolution of the AM EHEA offers new insights to guide the development of high-performance complex materials for extreme conditions.