Study On The Process Parameters And Properties Of Selective Laser Sintering W-Cu Composites

W-Cu composites consist of tungsten(W) and copper(Cu) which combine a series of excellent characteristics of both elements such as great hardness and strength, high thermal conductivity(TC), low coefficient of thermal expansion(CTE), high arc erosion resistance and etc. With all the extraordinary properties, W-Cu composites have broad applications and prospects for development in the fields of electronic industry, military, aerospace. However, it is difficult to get the W-Cu composites with high density, high performance and complex structure through conventional methods, given the properties of refractoriness and high-hardness of tungsten. Therefore, W-Cu composites were prepared by selective laser sintering(SLS) in this studies. The powder characteristics and forming process parameters for W-Cu composites were discussed, which provided important theoretical guidance for the actual industrial production.Firstly, the influence of particle size and shape of powders on the microstructure, the forming process and quality of W-Cu composites fabricated by SLS was discussed. The results show that the optimized powder combination is W powder and Cu powder with regular shape and its average particle size is 20?m.Then, the effects of SLS process parameters(laser power, scan speed, scan space, scan vector length) on the relative density of W-Cu composites were investigated. Ultimately, the optimized process parameters of SLS W-Cu composites have been achieved. The laser powder is 195W; laser scan speed is 700mm/s; laser scan space is 0.08mm; laser scan vector length is 1mm. The influence of laser energy density, the combined effects of various parameters, on the relative density, surface roughness and hardness of W-Cu composites was analyzed. In addition, we observe the microstructure of SLS W-Cu composites which was formed under the optimized process parameters, showing that the forming mechanism of SLS W-Cu composites was liquid phase sintering mechanism.Eventually, the influence of Cu content(25%?30%?40%)on the relative density, microstructure and properties of SLS W-Cu composites were compared and analyzed. The results show that with the increase of Cu content in the W-Cu laser-sintered samples, the relative density, TC and CTE increase gradually, but the surface roughness and hardness continue to decline. It can be seen in the microstructure that W-W contiguity and the particle size of W decreases with the increase of Cu content, and the state of W particle in Cu phase gradually changes from contact to isolation.