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微观结构的演化和变形机制在纳米晶体高级变形中

Pengtao Li¹, Aijuan Wang¹, Meng Qi¹

¹Shaanxi Province Key Laboratory for Electrical Materials and Infiltration Technology, School of Materials Science and Engineering, Xi'an University of Technology, Xi'an, Shaanxi 710048, China. ajwmxl@163.com.

|February 5, 2024

概括

在广泛的温度范围内研究了纳米晶 (NC-Ta) 的机械性能和变形机制. 温度显著影响临界粒度,影响航空航天,生物医学和电子领域的应用.

科学领域:

材料科学材料科学材料科学
纳米技术纳米技术
机械工程机械工程

背景情况:

的 (Ta) 取决于温度的机械性能和变形机制对于其在能源,电子和航空航天领域的使用至关重要.
了解纳米晶 (NC-Ta) 的行为是优化其在苛刻应用中的性能的关键.

研究的目的:

研究NC-Ta在广泛的温度谱 (100K到1500K) 中的微观结构和变形行为.
分析温度对NC-Ta.的临界粒度和变形机制的影响.

主要方法:

高性能Ta的结构分析,平均基底结构大小约为20 nm.
分子动力学 (MD) 模拟来分析NC-Ta在不同温度下的拉伸行为.
调查霍尔 - 佩奇关系和反向霍尔 - 佩奇关系,以了解粒径效应.

主要成果:

弹性模量随着平均颗粒大小的线性增加,达到接近1.8.的冲击因子.
根据Hall-Petch关系确定的临界颗粒大小大约为8.2 nm.
变形机制从Hall-Petch (较大的粒度) 转向逆Hall-Petch (较小的粒度) 由于粒度旋转,滑动或迁移,温度显著影响临界粒度大小.

结论:

温度对NC-Ta.的塑性变形的临界粒度有很大的影响.
弹性模量和脱位密度随着温度的增加而下降.
这些发现指导了为航空航天,生物医学和电子应用量身定制的多晶Ta材料的设计.

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