激光冲击热障涂层高温热循环应力演变及裂纹扩展的有限元模拟  

Finite element simulation of high temperature thermal cyclic stress evolution and crack propagation in laser shock processed thermal barrier coatings

作　　者：樊小可 陈瑞芳[1] 叶云霞[1] 花银群[1] 蔡杰 戴峰泽[1] Fan Xiaoke;Chen Ruifang;Ye Yunxia;Hua Yinqun;Cai Jie;Dai Fengze(School of Mechanical Engineering,Jiangsu University,Zhenjiang Jiangsu 212013,China)

机构地区：[1]江苏大学机械工程学院,江苏镇江212013

出　　处：《金属热处理》2025年第4期302-312,共11页Heat Treatment of Metals

基　　金：江苏省重点研发产业前瞻项目(BE2020037);镇江市重点研发计划(GY2019005)。

摘　　要：通过改变热生长氧化物(TGO)生长速率和形貌建立激光冲击(LSPed)热障涂层模型,与未激光冲击(Non-LSPed)涂层的界面应力进行对比仿真,从应力演化的角度分析激光改性对于热障涂层高温热循环的影响,并在TC/TGO界面引入内聚力单元,研究激光改性对热障涂层界面裂纹的影响。结果表明,相同TGO形貌下,在TGO表面,LSPed试样的应力值小于Non-LSPed试样,激光改性降低了此区域产生褶皱翘曲、层裂和剪切破坏的风险;在TGO/BC界面,氧化前期LSPed试样的应力值偏大,但在氧化后期Non-LSPed和LSPed试样应力值基本接近,表明LSP改性对于TGO/BC界面应力影响较小。不同TGO形貌下,整体上LSPed试样应力小于Non-LSPed试样,表明LSP改性可有效地降低涂层界面应力值。Non-LSPed试样在热循环35次时,TC/TGO界面在波峰位置区域出现裂纹,随着循环次数增大,裂纹向波谷处扩展,LSPed试样热循环50次后未出现裂纹。A laser shock processed(LSPed)thermal barrier coating model was established by changing the growth rate and morphology of thermally grown oxide(TGO),and the interfacial stress of the LSPed coating was simulated in comparison with those of the non-LSPed coating,so as to analyse the effect of laser modification on the high-temperature thermal cycling of the thermal barrier coating from the view of the stress evolution,and the cohesion units at the TC/TGO interface was introduced to study the effect of laser modification on the interfacial crack of the thermal barrier coating.The results show that for the same TGO morphology,the stress value of LSPed specimens is smaller than that of Non-LSPed specimens on the TGO surface,and the laser modification reduces the risk of fold warping,layer cracking,and shear damage in this region.At the TGO/BC interface,the stress value of LSPed specimens in the pre-oxidation period is larger,but in the late stage of the oxidation period,the stress values of Non-LSPed and LSPed specimens are close to each other,suggesting that the effect of LSP modification on the stress at the TGO/BC interface is relatively small.Under different TGO morphologies,the overall stress of LSPed specimens is smaller than that of Non-LSPed specimens,indicating that LSP modification can effectively reduce the stress value of the coating interface.After 35 thermally cycles,cracks appear at the wave peak position of the TC/TGO interface in the Non-LSPed specimen.As the number of cycles increases,the cracks extend towards the wave valley.However,no cracks appear in the LSPed specimen after 50 thermal cycles.

关 键 词：激光冲击 热障涂层 内聚力单元 裂纹 应力演变 有限元模拟 

分 类 号：TG178[金属学及工艺—金属表面处理]