应力梯度对7075铝合金残余应力松弛的影响
Influence of Stress Gradient on Residual Stress Relief of 7075 Aluminum Alloy
袁海洋1,2, 胡永会2
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作者单位：(1. 湖南信息职业技术学院 机电工程系, 湖南 长沙 410200; 2.中南大学 机电工程学院, 湖南 长沙 410083)
中文关键字：7075铝合金； 残余应力； 应力松弛； 应力梯度； 显微硬度； 硬度梯度
英文关键字：7075 aluminum alloy; residual stress; stress relief; stress gradient; microhardness; hardness gradient
中文摘要：分别采用淬火强化和表面喷丸强化工艺对7075高强铝合金试样引入结构和表层集中残余应力，研究循环载荷下具有不同残余应力状态的铝合金试样表层残余应力松弛规律。结果表明，淬火引入了单调的表面残余应力和显微硬度，而喷丸引入了表面残余应力梯度和显微硬度梯度。残余应力沿试样厚度方向分布的应力梯度为应力松弛的主要影响因素，可用于表征应力松弛程度。喷丸引入的表层残余应力均匀且梯度大，主要发生应力松弛；而淬火引入非均匀的结构应力且梯度较小，主要发生应力重分布。
英文摘要：Structural stress and surface residual stress were introduced by quenching and shot peening treatment on 7075 aluminum alloy, the residual stress relief under cyclic loading was studied. The results show that quenching introduces monotonic surface residual stress and microhardness, while shot-peening introduces surface residual stress gradient and microhardness gradient. Stress gradient along with the thickness direction has great influence on residual stress relief which could be utilized to characterize the size and rate of stress relief. Great stress relief would occur in the uniform surface residual stress introduced by shot-peening with a great stress gradient. However, stress re-distribution would occur in the non-uniform structural stress introduced by quenching with a low stress gradient.