在往复摩擦过程中冷喷涂Al基复合涂层孔隙的开裂行为  

Pore Feature and Cracking Behavior of Cold-sprayed Al-based Composite Coatings under Reciprocating Friction

作　　者：王金龙 王慧明[1] 李应举[2] 张宏毅 吕晓仁[1] WANG Jinlong;WANG Huiming;LI Yingju;ZHANG Hongyi;LV Xiaoren(College of Mechanical Engineering,Shenyang University of Technology,Shenyang 110870,China;Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China;Shenyang Aerospace Mitsubishi Motors Automobile Engine Manufacturing Co.,Ltd.,Shenyang 110179,China)

机构地区：[1]沈阳工业大学机械工程学院,沈阳110870 [2]中国科学院金属研究所,沈阳110016 [3]沈阳航天三菱汽车发动机制造有限公司,沈阳110179

出　　处：《材料研究学报》2024年第7期481-489,共9页Chinese Journal of Materials Research

基　　金：国防科技重点实验室基金(JCKY61420052021)。

摘　　要：在AZ31镁合金表面制备含30%Al_(2)O_(3)的Al基复合涂层,并观测其上孔隙的大小和形状,进行往复摩擦磨损实验测试复合涂层的摩擦性能并观测横截面孔隙处裂纹的产生,研究了在往复摩擦过程中冷喷涂Al基复合涂层孔隙的开裂行为。使用Abaqus和Python脚本建立椭圆形、三角形、矩形和无孔隙复合涂层模型、分析摩擦过程中涂层孔隙处的最大应力和摩擦后最表层的残余应力并讨论了复合涂层应力的有限元分析结果和往复摩擦中裂纹尺寸之间的关系。结果表明:在摩擦过程中复合涂层的应力集中主要产生在椭圆形、三角形和矩形孔隙的长轴端点或其尖角处;从表层到界面残余应力由拉应力转变为压应力再转变为拉应力,最大Mises应力和最表层的平均残余应力逐渐增大。椭圆形孔隙的裂纹从长轴端点萌生和扩展,三角形和矩形孔隙的裂纹起源于尖角处且裂纹的长度和宽度依次增大。有限元分析结果表明,在摩擦过程中涂层孔隙处Mises最大应力值的增大导致摩擦后最表层平均残余应力增大,从而使裂纹的长度和宽度增大。这些结果与往复摩擦实验结果一致。Al-based composite coatings containing 30%Al_(2)O_(3)were prepared on AZ31 Mg-alloy via cold-spraying technique.Then the pore feature and cracking behavior of Al-based composite coatings during reciprocating friction testing was assessed by means of a wear-testing machine,as well as and the location of crack initiation for relevant pores on the cross section of coatings.Meanwhile,models for composite coatings of elliptical-,triangular-,and rectangular-pores,and pore-free were respectively established using Abaqus and Python scripts,then the maximum stress of pores during friction and the residual stress on the top surface after friction were analyzed for the composite coatings.The relationship between stress finite element results and the size of cracks induced by reciprocating friction was discussed.The research findings indicated that stress concentration for elliptical-,triangular-,and rectangular-pores mainly occurred at the endpoints of the major axis or at their corners during friction.From the top surface to the interface,the residual stress transformed from tensile stress to compressive stress and then back to tensile stress.For elliptical-,triangular-,and rectangular-pores,the maximum Mises stress and average residual stress on the surface gradually increased.Cracks initiated and propagated from the endpoints of the major axis for elliptical pores,while cracks in triangular-and rectangular-pores originated from the corners,with corresponding increases in crack length and width.Finite element analysis revealed that the increase in the maximum Mises stress of poresduring friction led to an increase in the average residual stress on the surface after friction.This,in turn,resulted in larger crack dimensions,consistent with the findings from the reciprocating friction experiments.

关 键 词：金属材料 镁合金 冷喷涂 应力集中 孔隙形貌 

分 类 号：TH117[机械工程—机械设计及理论]