X射线法测量淬火铝合金厚板表面残余应力-中国材料进展

文章信息/Info

Title:: Experimental Measurement of Surface Residual Stresses of Quenched Aluminum Alloy Thick

Author(s):: HU Yonghui; WU Yunxin; CHEN Lei; GUO Junkang; (College of Mechanical and Electrical Engineering,Central South University,Changsha 410083，China)

摘要:: 采用无损X射线衍射技术测试了7075铝合金厚板淬火后表面残余应力水平与分布，得到了淬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，而X射线法在无应力或原始应力水平很低的场合效果欠佳。淬火铝板表面残余应力的测试结果呈正态分布，且淬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。

Abstract:: Surface residual stress distributions and general rules of quenched 7075 aluminum alloy thick plates were acquired 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 measurement 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,surface residual stress measurements of the plates showing normal distributions which indicate credibility and correctness of the measured stress distributions.Edge effect causes residual stress relaxation near the edges of plates during quenching process,in which the maximum relaxation may amount to 40% of initial stress and the region size occurring stress relaxation would be equal to the thickness of the quenched plate.