表面粗糙度对激光选区熔化TC4钛合金疲劳性能的影响  

EFFECT OF SURFACE ROUGHNESS ON FATIGUE PROPERTY OF TC4 TITANIUM ALLOY BY SELECTIVE LASER MELTING

作　　者：董登科[1] 陈安[1] 李小飞 张海英[1] DONG DengKe;CHEN An;LI XiaoFei;ZHANG HaiYing(Aircraft Strength Research Institute of China,Xi’an 710065,China;Chinese Aeronautical Establishment,Beijing 100012,China)

机构地区：[1]中国飞机强度研究所,西安710065 [2]中国航空研究院,北京100012

出　　处：《机械强度》2020年第5期1094-1098,共5页Journal of Mechanical Strength

摘　　要：针对沉积表面和机加表面激光选区熔化(SLM)成形TC4钛合金试验件,通过疲劳试验得到两种表面粗糙度下的细节疲劳额定值(DFR),同时借助扫描电镜研究表面粗糙度对SLM成形TC4疲劳性能的影响。结果表明:沉积表面的DFR值为235.1 MPa,机加表面的DFR值为283.3 MPa,后者疲劳性能优于前者。断口分析显示表面粗糙度对疲劳裂纹萌生方式影响显著,沉积表面疲劳裂纹源萌生于试验件的表面,断口粗糙,高低起伏比较明显,机加表面疲劳裂纹源起始于试验件内部,断口比较平坦。The fatigue characteristic of TC4 titanium alloy by selective laser melting(SLM)with two different surface roughness is investigated.The detail fatigue rating(DFR)values are achieved based on the fatigue tests.The fatigue fractography is observed by scanning electron microscope to find the reason for surface roughness modification.The results indicate that DFR value of as-built surface specimen is 235.1 MPa and machined surface specimen is 283.3 MPa.So the SLM TC4 specimen in machined surface has superior fatigue property.The surface roughness has a significant effect on the crack initiation site.The fatigue crack in as-built specimen initiates from surface.Fatigue crack in machined specimen initiates from inside to subsurface.The latter is flat and the former is relatively rough.

关 键 词：激光选区熔化 表面粗糙度 细节疲劳额定值 疲劳断口 

分 类 号：V216.3[航空宇航科学与技术—航空宇航推进理论与工程]