结构状态控制了金属玻璃中剪带传播的机制
Jinhua Yu1, Zhen Zhang2, Zhendong Sha3
1Center for Alloy Innovation and Design, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, China.
概括
金属玻璃 (MGs) 中的剪切带 (SB) 随着冷却速度的降低,从间歇传播转变为连续传播. 这种由结构变化和剪切转换区 (STZs) 驱动的过渡影响机械性能.
科学领域:
- 材料科学 材料科学 材料科学
- 计算材料科学科学 计算材料科学
- 机械工程 机械工程
背景情况:
- 剪切带 (SB) 对金属玻璃 (MGs) 的机械性能至关重要.
- 由于它们的快速,局部性质,观察SB原子化机制具有挑战性.
- 以前的模拟使用了极高的冷却速率 (10^10 K s^-1),与实验条件不同.
研究的目的:
- 在Mg65Cu25Y10 MGs中研究SB传播的原子尺度机制.
- 探索较慢的冷却速率 (低至10^4 K s^-1) 对SB行为的影响.
- 了解结构进化如何影响SB动态和机械性能.
主要方法:
- 混合分子动力学/蒙特卡洛模拟.
- 模拟的Mg65Cu25Y10 MGs在从10^10 K s^-1到10^4 K s^-1.1的冷却速度下制备.
- 分析了原子尺度的结构变化和SB传播动态.
主要成果:
- 随着降低冷却速度,观察到SB传播机制的质量转变.
- 过度灭的MG显示了通过STZ激活和凝聚的间歇性"停止和移动"SB传播.
- 缓慢冷却的MG由于局部剪切软化和大 vortex 场而表现出连续的 SB 传播.
结论:
- 摩托车的结构状况显著影响了SB启动和传播机制.
- 较慢的冷却速度导致更集体的结构反应和持续的SB传播.
- 调整结构状态为优化工程应用的MG机械性能提供了机会.
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