低循环疲劳损伤机制和高强度压缩石墨铁在不同温度下的寿命预测
Qihua Wu1, Bingzhi Tan2,3, Jianchao Pang2
1State Key Laboratory of Engine and Powertrain System, Weichai Power Co., Ltd., 197A Fushou East Street, Weifang 261061, China.
Materials (Basel, Switzerland)
|September 14, 2024
概括
高强度压缩石墨铁 (CGI) 在高温下表现出较低的抗拉强度和疲劳寿命. 观察到循环硬化,并提出了一种新的疲劳寿命预测方法.
科学领域:
- 材料科学 材料科学 材料科学
- 机械工程 机械工程
- 金工业是金工业的一个方面.
背景情况:
- 压缩石墨铁 (CGI) 是一种重要的工程材料.
- 了解CGI的高温机械行为对于其应用至关重要.
- 在不同的热条件下预测疲劳寿命需要详细的调查.
研究的目的:
- 研究高强度CGI (RuT450) 在不同温度 (25°C,400°C,500°C) 下的拉力和低周期疲劳性能.
- 分析温度和应变幅度对疲劳寿命和故障机制的影响.
- 开发和提出一种基于能量和损伤机制的疲劳寿命预测方法.
主要方法:
- 在25°C,400°C和500°C时对RuT450 CGI进行拉伸和低周期疲劳测试.
- 分析微观结构的变化,包括氧化物层的形成和裂的传播.
- 将实验数据与现有的疲劳寿命预测模型进行比较.
主要成果:
- 拉力强度随着温度的增加而下降,在更高的温度下下降更快.
- 在高温下,疲劳寿命显著下降,特别是在高应变幅度下.
- 循环硬化是显而易见的,在所有测试温度下,初始循环应力随着应变幅度的增加而增加.
- 在石墨周围形成氧化物层,随后在高温下观察到裂,改变了裂传播的依赖性.
结论:
- 高温显著降低了高强度CGI的疲劳性能.
- 观察到的微观结构变化,特别是氧化物形成,在高温疲劳失败中起着关键作用.
- 一种新的疲劳寿命预测方法整合了能量和损伤机制,为CGI材料提供了一种有前途的方法.
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