在微米尺度上的金属中持续的滑带核化和演变的异质性
Steven Lavenstein1, Yejun Gu1, Dylan Madisetti1
1Department of Mechanical Engineering, Whiting School of Engineering, The Johns Hopkins University, Baltimore, MD 21218, USA.
概括
在循环加载过程中,金属会形成持久滑动带 (PSB). 这项研究显示PSB在微米尺度上很常见,
科学领域:
- 材料科学
- 机械工程
- 金属工程
背景情况:
- 金属的疲劳损伤涉及不可逆转的脱位运动,裂的开始和传播.
- 在疲劳研究中,理解从无裂状态到裂状态的转变是一个重大挑战.
- 持续滑动带 (PSB) 是周期性加载期间与此过渡相关的关键微观结构特征.
研究的目的:
- 通过实地微疲劳实验,研究持续滑动带 (PSB) 的形成和演变机制.
- 在微米尺度上描述PSB的流行和行为.
- 连接微米尺度变形机制与金属中的散装尺度疲劳故障.
主要方法:
- 在现场进行微疲劳实验以观察PSB的形成.
- 用微观分析来研究微米尺度上的PSB演变机制.
- 在微米尺度上测量出位积累率,并与批量样本进行比较.
主要成果:
- 在循环负荷下的金属中发现持续滑动带 (PSB) 在微米尺度上普遍存在.
- 微米尺度上的脱位积累率低于批量样本,延迟了PSB核形成.
- 这项研究观察到PSB的逐渐和异质演变.
结论:
- 这些发现突显了微米尺度现象在疲劳损伤中的重要性.
- 现有的PSB形成和金属裂变的模型可能需要改进,以纳入渐进而异质的演变.
- 了解微米尺度的变形机制对于预测金属中的大规模疲劳故障至关重要.
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