The morphology of nanoscale γ lamellae strongly influences the mechanical properties of fully lamellar Ti-Al alloys; however, the coarsening mechanisms governing these nanostructures remain poorly understood. This work combines phase-field simulations and experiments to investigate the growth and coarsening of γ lamellae. It reveals multiple lamellar orientation-dependent coarsening mechanisms, including coalescence, Ostwald ripening, and internal interface migration. The simulated planar or step-like γ/γ interfaces agree well with the experimental observations. The competing effects between elastic energy and chemical driving force on the evolution kinetics of γ lamellae are quantitatively characterized. Elevated elastic energy suppresses coarsening and refines the lamellar structure, whereas a large chemical driving force accelerates precipitation, coarsening, and splitting. A four-stage kinetic sequence is identified for γ lamellar evolution: nucleation and growth, quasi-steady-state coarsening, splitting, and steady-state coarsening. These findings offer novel insights into the complex coarsening mechanisms and kinetic pathways of multi-variant γ lamellae in γ-TiAl alloys.
NiTi shape memory alloys (SMAs) exhibit outstanding pseudoelasticity, yet the strongly first-order nature of their martensitic transformations (MTs) produces autocatalytic strain avalanches and large hysteresis that limit controllability and energy efficiency. Recent experiments have shown that severe plastic deforma...
Tai-Wu Yu, Vidyanidhi Kabanur, Jia-Ming Zhu et al.· Smart materials and structur...· 0 citations
Grain boundary engineering is a major avenue for tailoring the mechanical behavior of polycrystalline materials. Grain boundary complexions, including amorphous intergranular films, are classically accessed through thermal driving forces and solute segregation. Here, we discover that plastic deformation can drive amorp...
M. Ahmadi, Jin Qin, Gabrielle Tiphéne et al.· 0 citations
AlCoCrFeNi eutectic multi-principal element alloys exhibit remarkable application potential owing to their inherent heterostructures and outstanding mechanical properties. Their mechanical behaviors are governed by the synergistic deformation of non-uniformly distributed face-centered cubic (FCC) and B2 phases. Clarify...
Hai-Feng Zhang, Nan Jia, Ming-Ming Wang et al.· Microstructures· 0 citations
Nanocrystalline Al-Zn-Mg alloys are pivotal for next-generation aerospace and automotive applications that require superior strength-to-weight ratios. However, optimizing their mechanical properties at the atomic scale remains a challenge because classical strengthening theories break down. This study employs molecular...
Kun Gao, Long-Zhou Huang, Jia-Ni Yan et al.· Small· 0 citations
Many nanosized metals with limited dislocation nucleation and multiplication usually exhibit poor plasticity. Previous studies have demonstrated that multi-principal element alloys (MPEAs) can achieve a combination of strength and plasticity. However, whether these mechanical properties extend to their nanosized co...
Yan Ma, Zhan-Xin Wang, Jia-Bao Zhang et al.· Nature Communications· 0 citations
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