乙集需0集 2011年2月
中国材料进展 MATERIALS CHINA
Vol.30
No.2 Feb.2011
X射线法测量火铝合金厚板表面残余应力
胡永会，吴运新，陈磊，郭俊康（中南大学机电工程学院，湖南长沙410083）
要：采用无X射线衔射技术测试了7075铝合金厚板痒火后表面残余应力水平与分布，得到摘
了萍火铝合金厚板表面残余应力的分布区间和一般规律，分析了准直管对测试结果的影响，并与中心钻孔法得到的结果做了比较。结果表明，两种方法都能有效并正确测量构件的表面残余应力，但中心钻孔法不适合用于应力梯度大的场合，面X射线法在无应力或原始应力水平很低的场合效果欠佳。痒火铝板表面残余应力的测试结果呈正态分布，且痒火过程中边缘局部有应力释放，释放值可达40%，且此区域大小约为铝板的一个厚度。
关键词：X射线街射法；7075错合金；残余应力；中心钻孔法；边缘效应
中图分类号：TG115.22；TC146.21
胡永会
(2011)02 0051 05
文献标识码：A
文章编号：1674-3962
ExperimentalMeasurementofSurfaceResidual Stresses of Quenched Aluminum Alloy Thick
PlatebyX-RayMethod
HU Yonghui, WU Yunxin,
CHEN Lei, GUO Junkang
( College of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China)
Abstract: Surface residual stress distributions and general rules of quenched 7075 aluminum alloy thick plates were ac-quired by non-destructive X-ray diffraction method, in which effects of collimators were analyzed and the stress results were co MPared with measurements from center drilling method. The results show that both of the two surface stress meas-urement methods are effective and correct. But center drilling method is not suitable to conditions with large stress gradient while X-ray method is not effective in conditions where there is no stress or very low initial stress level. In addition, sur-face residual stress measurements of the plates showing normal distributions which indicate credibility and correctness of
Edge effect causes residual stress relaxation near the edges of plates during quenching
the measured stress distributions.
process, in which the maximum relaxation may amount to 40% of initial stress and the region size oceurring stress relaxa-tion would be equal to the thickness of the quenched plate.
Key wOrdS : X-ray diffraction method; 7075 aluminum alloy; residual stress; center drilling method; edge effect
1
前言
7075高强错合金厚板是航空航天与武器装备工业
中使用广泛的关键性结构材料，然而在其成形和热处理过程中引人的残余应力造成工件变形和尺寸不稳定，是长期困扰工程界的技术难题"-21。由于X射线法的无损与理论成熟等特性，配合材料表面的逐层剥除，目前正被广泛应用于高强铝合金的表层残余应力测试与研究工
收稿日期：201006-19
基金项目：国家重点基础研究发展规划（973计划）资助
(2005CB623708; 2010CB731703)
通信作者：胡永会，男，1985年生，硕十研究生
作中3-6
本文采用X射线衍射法测量率火7075铝合金厚板的表面残余应力，研究其应力分布区间与一般规律，并与中心钻孔法得到的结果比较分析，讨论X射线测量结果的可信度与正确性。试验结果表明，X射线法与中心钻孔法测试结果稍有差别，但皆可有效并正确测试出率火铝合金厚板的表面残余应力，实际应用中可互补验证。但是二者的应用场合受限于初始残余应力状态，初始局部应力梯度大将对中心钻孔法测量结果产生影响，而无应力或初始应力水平很低的情况下，X射线衍射法测试结果将引人较大误差。残余应力测试结果也表明，淬火板表面残余应力呈正态分布特性，且在漳火过程中厚板边缘发生大幅应力释放，影响区域约为一个铝板厚度。