GH4169电子束焊接头高温疲劳寿命预测模型
High-temperature fatigue life prediction model of GH4169 electron beam welding joint
刘小刚 1李张辉 1于盛吉 1彭伟平2
作者信息
- 1. 南京航空航天大学能源与动力学院,南京 210016
- 2. 江苏奇纳新材料科技有限公司,江苏宿迁 223802
- 折叠
摘要
为建立GH4169电子束焊接头的高温疲劳寿命预测模型,开展了电子束焊接头多个温度下的疲劳试验,获得其不同温度下的应力-寿命(S-A)曲线,分析了温度对接头疲劳性能的影响规律.对疲劳断口进行金相分析和扫描电镜(SEM)观测,研究其高温疲劳损伤机理.结果表明,温度对接头疲劳性能的影响与载荷水平有关,当应力水平大于980 MPa时,随温度升高,接头的疲劳性能呈现明显的下降趋势;此外,接头室温下为穿晶脆性断裂,而高温下呈现出解理断裂特征.在上述分析基础上,考虑屈服强度及晶粒尺寸随温度的变化,结合疲劳试验数据对Basquin模型中材料参数进行修正,建立电子束焊接头高温疲劳寿命预测模型.结果表明:当仅考虑屈服强度因素对参数进行拟合,模型的预测精度较低,而综合考虑屈服强度及晶粒尺寸的影响,修正后的模型预测精度较高,其误差在±2倍分散带以内.
Abstract
In order to establish the high-temperature fatigue life prediction model of GH4169 electron beam welded joints,fatigue tests at different temperatures were carried out to obtain the stress-life(S-N)curves respectively.The influence of temperature on the fatigue performance of joints was analyzed.The fatigue damage mechanism was studied by metallographic analysis and scanning electron microscope(SEM)test.The results showed that the effect of temperature on the fatigue performance of the joint was related to the load level.Under the load above 980 MPa,the fatigue performance showed an obviously downward trend with the increase of temperature.In addition,the fracture mechanism of joints presented transgranular brittle fracture at room temperature and cleavage fracture at high-temperature.On the basis of the above analysis,considering the changes of yield strength and grain size with temperature,the parameters in Basquin model were modified in combination with fatigue test data,and the high-temperature fatigue life prediction model of welded joints was established.The results showed that the prediction accuracy of the modified model was high when the yield strength and grain size were considered comprehensively,while the accuracy of the model was within±2 times of the dispersion band.
关键词
高温疲劳/GH4169合金/电子束焊接头/疲劳寿命预测模型/疲劳损伤机理Key words
high-temperature fatigue/GH4169 alloy/electron beam welding joint/fatigue life prediction model/fatigue damage mechanism引用本文复制引用
基金项目
国家科技重大专项(J2019-Ⅳ-0008-0076)
中央高校基本科研业务费专项(NS2021014)
出版年
2024
NETL
NSTL
万方数据