Annealing twins (ATs) are prevalent in face-centered cubic (FCC) metals/alloys and significantly influence their mechanical properties. Therefore, understanding the formation capability of ATs is crucial for controlling the mechanical properties of FCC metals/alloys. Although the "Stacking Fault Energy" is a widely used factor to characterize AT formation capability, it doesn't comprehensively explain the observed experimental rankings of AT formation capability. In this study, through a combination of experiments and molecular dynamics simulations, we demonstrated that AT growth is primarily driven by the migration of the Σ3 incoherent twin boundary. This migration arises from the elastic strain energy imbalance between grains on either side of the twin boundary caused by the elastic anisotropy of crystal. Based on these findings, we propose a new criterion, defined as a ratio of the coherent twin boundary energy to the anisotropy factor, to represent the AT formation capability (inverse relationship). Such new criterion well explains the experimental observation, and can be generalized to the zero macroscopic strain deformation twin.

中文翻译：

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面心立方金属/合金中退火孪晶形成能力的新判据


退火孪晶 (AT) 在面心立方 (FCC) 金属/合金中普遍存在，并显着影响其机械性能。因此，了解 AT 的形成能力对于控制 FCC 金属/合金的机械性能至关重要。虽然“堆垛层错能量”是广泛使用的表征AT形成能力的因素，但它并不能全面解释观察到的AT形成能力的实验排名。在这项研究中，通过实验和分子动力学模拟相结合，我们证明了 AT 的增长主要是由 Σ3 非相干孪晶边界的迁移驱动的。这种迁移是由晶体的弹性各向异性引起的孪晶边界两侧晶粒之间的弹性应变能不平衡引起的。基于这些发现，我们提出了一个新的标准，定义为相干孪晶边界能量与各向异性因子的比率，来表示AT形成能力（反比关系）。这种新准则很好地解释了实验观察，并且可以推广到零宏观应变变形孪晶。