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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。
The structure and surface concentrated residual stresses of 7075 high strength aluminum alloy specimens were respectively quenched and surface shot peening strengthened to study the residual stress relaxation rules of aluminum alloy specimens with different residual stress under cyclic loading. The results show that quenching introduces monotonous surface residual stress and microhardness, while shot peening introduces surface residual stress gradient and microhardness gradient. The stress gradient along the thickness direction of specimen is the main factor of stress relaxation and can be used to characterize the degree of stress relaxation. The surface residual stress introduced by shot peening is uniform and the gradient is large, and the stress relaxation occurs mainly. However, the quenching introduces non-uniform structural stress and the gradient is small, and the stress redistribution mainly occurs.