孔内壁残余应力和表面粗糙度对7050铝合金紧固孔试样疲劳寿命的影响  

Effect of Residual Stress and Surface Roughness of Hole Inner Face on Fatigue Life of 7050 Aluminum Alloy Fastener Hole Sample

作　　者：刘长军[1] 戴寅 常帅 谈建平[1,2] LIU Changjun;DAI Yin;CHANG Shuai;TAN Jianping(Key Laboratory of Pressure Systems and Safety,Ministry of Education,East China University of Science and Technology,Shanghai 200237,China;Shanghai Institute of Aircraft Mechanics and Control,Shanghai 200237,China)

机构地区：[1]华东理工大学承压系统与安全教育部重点实验室,上海200237 [2]上海飞行器力学与控制研究院,上海200237

出　　处：《机械工程材料》2025年第1期23-29,共7页Materials For Mechanical Engineering

基　　金：国家自然科学基金资助项目(52075174);上海高校IV类高峰学科建设项目。

摘　　要：通过不同切削速度(4,8,12,16,20,40,80 mm·min-1)钻铰、不同进给速度(0.02,0.04 mm·r-1)铣削和电火花加工,在7075-T72451铝合金疲劳试样中心制备了不同表面粗糙度和残余应力的紧固孔,通过高周疲劳试验研究了孔表面粗糙度和残余应力对试样疲劳寿命的影响,建立了孔表面粗糙度和残余应力与疲劳寿命之间的关系。结果表明:3种工艺加工孔中,钻铰孔表面质量最好,可以通过增加切削速度在维持较小表面粗糙度的同时增大残余压应力。表面粗糙度和残余应力共同影响疲劳寿命,表面粗糙度较小时,随着残余压应力增加,疲劳寿命延长;表面粗糙度增大后,应力集中效应对疲劳寿命影响的占比变大,残余应力的影响占比变小,疲劳寿命缩短;切削速度为16 mm·min-1时钻铰孔试样疲劳寿命最长;提出的综合考虑表面粗糙度和残余应力影响的孔表面质量影响系数能在±2.5倍数据分散带内很好地关联疲劳寿命。Theϕ2.6 mm fastener hole with different surface roughness and residual stress were prepared on 7050-T7451 aluminum alloy fatigue samples by drilling and reaming under different cutting speed(4,8,12,16,20,40,80 mm·min−1),milling under different feed speed(0.02,0.04 mm·r−1)or electrical discharge machining respectively.The effect of hole surface roughness and residual stress on fatigue life was studied by high cycle fatigue test,and the correlation between hole surface roughness and residual stress and fatigue life was established.The results show that among three kinds of processed holes,the surface quality of drilling and reaming holes was the best;increasing the cutting speed could improve the residual compressive stress and maintain a small surface roughness.Surface roughness and residual stress jointly affected the fatigue life.When the surface roughness was small,the fatigue life was extended with the increase of residual compressive stress.When the surface roughness increased,the proportion of stress concentration effect on fatigue life increased,while the proportion of residual stress effect decreased,resulting in the decrease of fatigue life.When the cutting speed was 16 mm·min−1,the fatigue life of the drilling and reaming hole was the longest.The hole surface quality influence coefficient comprehensively considering the influence of surface roughness and residual stress could correlate the fatigue life well in the±2.5 times data dispersion band.

关 键 词：孔加工 疲劳寿命 表面粗糙度 残余应力 

分 类 号：TG501.2[金属学及工艺—金属切削加工及机床]