液氮深冷处理对2195铝锂合金残余应力的影响研究

Research on the Effect of Liquid Nitrogen Cryogenic Treatment on Residual Stress of 2195 Al-Li Alloy

液氮深冷处理可改善材料力学性能并消减残余应力。通过采集2195铝锂合金材料深冷处理过程中的温度梯度,获得各过程的热交换系数,建立了2195铝锂合金液氮深冷残余应力演变的有限元预测模型,分析了深冷处理对材料应变和应力的影响规律。采用层削法残余应力测试技术对材料内部残余应力进行了测试,验证了液氮深冷处理对残余应力的消减作用。结果表明,与淬火态相比,深冷处理后材料表面和心部的压缩真应变减小,表面和心部的塑性应变差值减小,表面压应力峰值降低5.9%,心部拉应力峰值降低13.1%。研究表明,深冷处理可降低材料的残余应力水平。

Liquid nitrogen cryogenic treatment can improve the mechanical properties of materials and reduce residual stress.In this study,by collecting temperature gradients during the cryogenic treatment process of 2195 Al-Li alloy materials,the heat transfer coeffi-cients of each process were obtained.A predictive model for the evolution of residual stress in 2195 aluminum-lithium alloy with liq-uid nitrogen cryogenic treatment was established,and the effect of cryogenic treatment on material strain and stress was analyzed.The layer removal method residual stress testing technique was also used to test the internal residual stress of the materials,confirming the re-duction effect of liquid nitrogen cryogenic treatment on residual stress.The research results show that compared to the quenched state,the compressive true strain on the surface and in the core of the material decreases after cryogenic treatment,the difference in plastic strain between the surface and core decreases,the peak compressive stress on the surface decreases by 5.9%,and the peak tensile stress in the core decreases by 13.1%.Cryogenic treatment can reduce the level of residual stress in materials.