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7075铝合金试样经3种喷丸工艺引入残余应力并进行循环应力试验,测试各加载周期下的残余应力与显微硬度,分析循环载荷下的残余应力松弛规律。结果表明,残余应力与显微硬度同是局部晶格畸变与塑性变形的宏观体现,在宏观应力载荷下演化趋势关系密切。且残余应力松弛特性与显微硬度演化规律主要受初始分布状态与循环应力水平控制,而循环周期的作用主要体现在前期,呈现出初期无规则大幅变化及中后期稳定小幅规律变化趋势。
The residual stress and microhardness of 7075 aluminum alloy specimen were introduced into three kinds of shot peening process by residual stress and cyclic stress test. The residual stress relaxation under cyclic loading was analyzed. The results show that the residual stress and microhardness are the same macroscopical reflection of local lattice distortion and plastic deformation, and the evolution trend is closely related to the macro-stress load. The evolution of residual stress relaxation and microhardness is mainly controlled by the initial distribution and cyclic stress level. However, the effect of the cycle is mainly reflected in the early stage, showing a sharp change in initial irregularity and a steady trend in small and medium regularity.