单/多晶铁低循环疲劳行为的分子动力学模拟
Tianyu Zhang1,2, Jinjie Zhou1,2, Jinchuan Shen1,2
1School of Mechanical Engineering, North University of China, Taiyuan 030051, China.
Nanomaterials (Basel, Switzerland)
|February 13, 2025
概括
这项研究利用分子动力学揭示了疲劳损伤如何在铁中启动和积累. 单晶铁在滑动平面交叉点上表现出塑性疲劳,而多晶铁则经历了谷物边界损伤.
科学领域:
- 材料科学 材料科学 材料科学
- 机械工程 机械工程
- 凝聚物质物理学 凝聚物质物理学
背景情况:
- 了解疲劳塑性机制和脱位特征对于研究材料疲劳损伤至关重要.
- 工程材料在循环负荷下容易发生疲劳故障,需要对潜在机制进行详细的研究.
研究的目的:
- 研究单晶和多晶铁的微观结构特性和疲劳力学特性.
- 分析不同应变幅度下的局部塑料疲劳损伤的发生,积累和形成过程.
主要方法:
- 采用分子动力学 (MD) 方法来模拟疲劳行为.
- 检查了单晶和多晶铁结构.
- 在循环硬化,软化和和条件下分析了反应.
主要成果:
- 在单晶铁中,局部塑料疲劳在滑动平面交叉点开始并积累,作为脱位源,1/2<111>脱位是显著的.
- 多晶铁在循环加载时表现出颗粒旋转和凝聚,导致颗粒大小增加,导致塑料变形.
- 塑性在多晶铁的粒边界开始并积累,最终导致疲劳损伤.
结论:
- 该研究阐明了单晶与多晶铁在微观结构层面上的明显疲劳损伤机制.
- 确定了疲劳启动的关键位置 (单晶中的滑平面交叉点,多晶体中的粒度边界).
- 突出了特定脱位和粒度演变在材料疲劳抵抗中的作用.
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