The Surface Modification Research Of 6061 Aluminum Alloy Based On Friction Stirs Processing

Aluminum alloy has been widely used in modern industry and life, plays an irreplaceable role, but due to defects in its strength, wear resistance, corrosion resistance and other properties to limit its application in a particular environment.the performance of aluminum improved treatment, can make it wider range of applications. The composites are bulk prepared by conventional processing methods, such material is brittle,and has bad ductility, low toughness, and the data shows 80% of mechanical failure were from surface wear, if use new reinforcement technique was used to prepare surface composite material, can achieve material wear-resisting performance and can maintain the ductility and toughness of raw materials, therefore, the new surface strengthening technology is more and more get the attention of people.Friction stir processing is a new kind of high quality, green environmental protection of surface strengthening technology. At present has been widely used in materials such as magnesium, aluminum workpiece surface strengthening. In this paper, using the friction stir processing of 6061 aluminum alloy surface treatment technology, different technological parameters and the study of the processing layer mixing head surface morphology, the influence of the structure, microhardness, determine the best process parameters. Using optimized process parameters, the preparation of SiC/Al matrix surface composites, and the SiC particles microhardness of the composites layer, the influence of the friction and wear performance, analyzed the heat treatment on the properties of composite material layer organization and influence.The results show that: different mixing heads at different process parameters on the performance of a great influence processing zones, using concentric mixing head, the speed of 1100 rpm, forward speed 100 mm / min, under the pressure of the amount of parameters 0.5mm, 1.5°inclination under processing layer on the surface to get the best of shape, micro maximum hardness, the average hardness of 107 HV, relative to the base metal hardness increased by 18%.In the aluminum surface processing array blind holes and dovetail to fill SiC particles, after capping and segmentation processing, using concentric mixing head of SiC under these optimal parameters Al composites based surface layer. The results show that: the composite layer slotted array of blind holes more uniform manner than good, slotted array blind dovetail SiC particle distribution methods, higher hardness, the composite layer of SiC particles produced at the bottom of the dovetail groove machining area aggregation. Hardness of the composite material layer with SiC volume fraction was increased, the volume fraction higher than 20% of both the linear relationship, when the volume fraction was 44%, the highest hardness values, up to 179 HV, the hardness of the base material is 1.96 times. The results show that the heat treatment: after solution treatment and artificial aging treatment that can eliminate defects weaken heat affected zone and heat affected zone, the average hardness after heat treatment than before the heat treatment increased by 45% over the base metal zone increased by 26%. The results show that the friction and wear: Wear properties of the composite material layer is significantly higher than the base metal at low load condition, the wear rate of the composite material is 44% of the base, in the high-load condition, the wear rate of the composite base material 56%. The wear of the composite material layer increases with increasing load, with increasing SiC content is reduced; friction coefficient with increasing load and the SiC content is reduced.