膜致应力对氧化膜和基体金属内应力的影响  

Influence of membrane induced stress on internal stress of oxide film and substrate metal

作　　者：张文娟 杨帆[1] 乔铁良 Zhang Wenjuan;Yang Fan;Qiao Tieliang(Xi’an Aeronautical Polytechnic Institute,Xi’an 710089,China)

机构地区：[1]西安航空职业技术学院,西安710089

出　　处：《焊接》2024年第8期47-51,60,共6页Welding & Joining

基　　金：陕西省教育厅一般专项科学研究项目(23JK0505)。

摘　　要：【目的】旨在了解氧化膜所产生的裂尖膜致应力对表面缺陷和应力腐蚀开裂历程中所带来的力学影响规律。【方法】以镍基合金600为研究对象,建立SCC全寿命周期膜致应力有限元模型,得出不同ΔT下膜致应力对氧化膜和基体金属裂尖力学场的影响。【结果】氧化膜内产生的压应力给基体金属裂尖带来附加拉应力,这个拉应力为膜致应力,加速了氧化膜的破裂;随着温度的升高,氧化膜和基体金属中的膜致应力均增大,但氧化膜内的应力增幅大于基体金属裂尖;在氧化膜和基体金属界面处,Mises应力和拉伸应力都发生了阶跃现象,提升了裂尖的SCC敏感度。【结论】膜致应力在裂纹萌生初期的作用不可被忽略,会造成膜的破裂和基体金属的裸露,引起微裂纹的形核和扩展。[Objective]The purpose was to understand mechanical effects of crack tip film induced stress generated by oxide film on surface defects and stress corrosion cracking processes.[Methods]Taking nickel based alloy 600 as the research object,a finite element model of SCC full life cycle film induced stress was established,and influence of film induced stress on mechanical field of oxide film and matrix metal crack tip under differentΔT was obtained.[Results]Compressive stress generated within oxide film brought additional tensile stress to crack tip of substrate metal,which was film induced stress and accelerated rupture of oxide film.As temperature increased,film induced stress in both oxide film and substrate metal increased,but stress increase in oxide film was greater than that at the crack tip of substrate metal.At the interface between oxide film and substrate metal,both Mises stress and tensile stress exhibited a step phenomenon,which enhanced SCC sensitivity of crack tip.[Conclusion]The role of membrane induced stress in early stage of crack initiation couldn’t be ignored,it could cause membrane rupture and exposure of substrate metal,leading to nucleation and propagation of microcracks.

关 键 词：氧化膜 基体金属 膜致应力 裂纹尖端 

分 类 号：TG404[金属学及工艺—焊接]