在独立的纳米晶体和金薄膜中回收塑料变形
Jagannathan Rajagopalan1, Jong H Han, M Taher A Saif
1Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
概括
纳米晶体金属中的塑料变形,与粗粒金属不同,在卸载后显示出显著的应变回收 (50-100%). 这种取决于时间和温度的现象在和黄金片中被观察到.
科学领域:
- 材料科学 材料科学 材料科学
- 纳米技术纳米技术
- 固体力学 固体力学是什么
背景情况:
- 纳米晶体金属表现出明显的塑性变形机制,这是由于与粗粒相比,有限的粒体内脱位源.
- 金属中的塑料变形传统上被认为是一个无法恢复的过程,不管颗粒大小如何.
研究的目的:
- 研究纳米晶和金膜中的塑料应变的可回收性.
- 描述应变恢复的时间和温度依赖性.
- 检查应变恢复对后续加载行为的影响.
主要方法:
- 纳米晶体 (65纳米粒径) 和金 (50纳米粒径) 薄膜的实验变形.
- 卸载和观察随着时间的推移和不同温度的应变恢复.
- 随后的加载周期,以评估应力-应变特征.
主要成果:
- 塑料变形的纳米晶体和金片在卸载时恢复了相当大一部分 (50-100%) 的塑料应变.
- 观察到应变恢复是时间依赖的,并且因温度升高而加速.
- 在随后的加载周期中,应力-应变行为在完全恢复后基本保持不变.
结论:
- 塑料应变回收是纳米晶体和黄金薄膜变形的一个显著特征.
- 这些发现表明,应变恢复可能是其他纳米晶体面中心立方金属的一般现象.
- 这挑战了塑料变形的传统理解,即塑料变形是完全无法恢复的.
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