Study On Heat Treatment Process And Mechanical Property Of In-situ Preparation Aluminum Matrix Composites

Compared with the traditional metal material, aluminum and composite materials have a series of advantages:specific strength than stiffness, good formability, dimensional stability, strength and corrosion resistance, so it is extremely broad prospects for development in the automotive, electronics, aerospace and other industries field.This paper adopts high-energy ultrasound in situ prepared AI3T1/7075 matrix composites, prepared under the traditional method to solve the composite materials with enhanced uniform particle distribution and to enhance the bonding between particles and other issues. On the preparation of the aluminum matrix composite micro structure and mechanical properties of phase analysis showed that:Al3Ti reinforcing particles distributed uniformly in the matrix, grain size small, Al3Ti particles and the bonding is good.To further improve the mechanical property of composite, the solution and aging treatment of Al3Ti/7075 composite was analyzed with box heat treatment furnace, microhardness device, SEM and EDS. The results showed that:composite materials, the best single-stage solution treatment method is 480℃/5h, composite materials after solution treatment for this condition, the second phase can be a good solution back to the base body and the grain does not occur long phenomenon. The higher solution temperature, dissolved solute atoms is limited, the strengthening effect of solute atoms do not bring the alloy hardness of a downward trend, when the solution temperature reaches 520℃, the emergence of the phenomenon of organized burn.The best way of two-stage solution treatment is 440℃/3h+480℃/2h. Compared with single-stage solution treatment, composite materials in this condition, after solution treatment, composite materials maximum solubility, the second phase back to more fully dissolved solution treatment and maximum hardness. Aging behavior of the composites were analyzed, the results showed that:the matrix alloy and composites at the same temperature aging, the composite material to reach the peak aging time shorter than the matrix alloy; the hardness of Al3Ti/7075 aluminum matrix composites higher than the matrix, mainly because of the high-energy ultrasound used to make composite materials, grain refinement and in situ reaction of Al3Ti particles can be uniformly distributed in the matrix.Dry sliding wear behaviour of extruded Al3Ti/7075composites and 7075 matrix were investigated with wear test mechine,electronic balance and SEM, the results show that:several abrasion mechanism result in the wear of composite and matrix alloy; with the rise of sliding speed and load, the wear rates of composites and matrix increase; In the same friction condition, the wear performance of composites higher than the matrix; At low load wear in composite material, due to the existence of reinforcing particles that composites wear performance is better than matrix; As the load increased, enhanced particles fracture or loose from the matrix, which is bound to reduce the friction contact area, breaking the rest of the play is still the matrix enhancement to improve the wear properties of composite materials.