Abstract Twinning is an important mechanism during the plastic deformation of materials with hexagonal-close-packed crystal structure. Strength and formability are critical properties for this family of structural materials and can consequently be improved by controlling twin nucleation and growth. Here, we study the effect of alloying elements on strain rate and temperature dependence of twin growth. Without using any fitting parameters, we derive an analytical model which takes atomic scale calculated parameters as input and predicts the equilibrium concentration of segregated solutes and strengthening due to solute-twin interactions. This model predicts the strain-rate/temperature conditions of negative strain rate sensitivity in titanium, under loading conditions that favor twinning, with oxygen interstitial. The predictions are in agreement with available experiments. Our findings present a new mechanism for dynamic strain aging as a result of solute segregation to the twin boundaries.

中文翻译：

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溶质/孪晶界相互作用作为动态应变老化的新原子尺度机制

摘要 孪晶是六方密排晶体结构材料塑性变形过程中的重要机制。强度和可成形性是这一系列结构材料的关键特性，因此可以通过控制孪生成核和生长来提高。在这里，我们研究了合金元素对孪晶生长的应变速率和温度依赖性的影响。在不使用任何拟合参数的情况下，我们推导出了一个分析模型，该模型以原子尺度计算参数为输入，预测分离溶质的平衡浓度和由于溶质孪生相互作用而引起的强化。该模型预测了钛中负应变率敏感性的应变率/温度条件，在有利于孪晶和氧间隙的加载条件下。这些预测与可用的实验一致。由于溶质偏析到孪晶界，我们的研究结果提出了动态应变时效的新机制。