| This article mainly studied on how the residual stresses and microstructures of SiC_w/Al MMC are affected by different shot peening treatments, and stress relaxation of SiC_w/Al MMC under heat. Additionally, a finite element analysis method (FEA) is used to simulate shot peening process. Some parameters such shots'material, size, speed and overlay ratios are studied to learn how these parameters affect the distribution of residual stress inside SiC_w/Al MMC. With some simplified methods, a heterogeneous model of shot peening on SiC_w/Al MMC is built. With this model, the micro region distribution of residual stress in plastic deformation area is observed. We also learnt how the size and distribution of whisker reinforcements affect the deformation and stresses of metal matrix.The results of traditional shot peening treatments reveal that the characteristic parameters of residual stress field can be improved by increasing of peening intensity, while the maximum residual stress is limited by SiC_w/Al MMC properties itself. With improved peening methods such as warm peening, stress peening and compound peening, the characteristic parameters of residual stress field can be improved further which has an important meaning to industrial production field.After shot peening, we did some heating treatment to study stress relaxation of SiC_w/Al MMC, the results show that when the heating temperature goes up to 200℃, residual stress in SiC_w/Al MMC relaxed sharply within 10minutes, and residual stress even changed from compressive to tensile. When the heating temperature is about 100℃, residual stress just relaxed partly.ODF function results show that after shot peening, original texture inside SiC_w/Al MMC didn't disappear or decrease as other materials did. The original texture on surface layer disappeared, while beneath surface, shot peening treatment changed the components of texture from {1 10} 112 to{1 12} 110 , the intensity of texture didn't reduce so much. This result means that in SiC_w/Al MMC, the plastic deformation of metal matrix is constrained by whisker reinforcements and tends to be uniform of whisker reinforcements'orientation.With a FEA shot peening homogeneous model, we studied how some peening parameters such shots'material, size, speed and overlay ratios affect the distribution of residual stress inside SiC_w/Al MMC. Numerical simulation results show that these parameters take different effects in shot peening treatment. Overlay ratios can improve the maximum residual stress, compressive stress depth and reduce roughness of surface. Different shot material means different density, higher density shots can affects deeper and the value of residual stress is larger. The size of shots is directly related to the depth of compressive stress. With smaller shots, the maximum residual stress is bigger while compressive stress reduces faster in the depth direction. Large shots are easier to generate a deep compressive stress field but maximum stress value is smaller. Shots'speed is highly related to the value of tensile stress beneath compress stress field. Higher speed shot peening can affect deeper and the maximum tensile stress falls sharply.An inhomogeneous peening model is built to study residual stress distribution in micro region of plastic deformation area. Since the mechanical properties between reinforcements and metal matrix are quite different, the stress field in these two materials is discontinuous. In reinforcements, tensile stress is generated after shot peening, while in matrix, residual stress is mostly compressive. Plastic deformation of metal matrix is obviously constrained by whisker reinforcements because the stress field in matrix is similar to the distribution and orientation of whisker reinforcements. Between whiskers, high compressive stresses are obtained, but on two top side area of whisker, compressive stresses are smaller and even some tensile stresses are observed.
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