铜粉对MIM钨铜合金组织和性能的影响

采用金属注射成形（MIM）技术制备了钨铜合金，定量表征了铜粉的粉末粒度和粒形，重点研究了铜粉粒度和粒形对MIM钨铜合金组织与性能的影响。通过对比铜粉的粒径、粒度分布宽度、长宽比、粗糙度、赘生物指数和钝度等特征参数，破碎铜粉与水雾化铜粉颗粒呈枝晶状，粒径远小于还原铜粉，但破碎铜粉粒度分布宽，微观结构上的规则度、表面光滑程度以及分散程度最佳。破碎铜粉混合钨粉为原料，通过MIM技术制备钨铜注射生坯致密度高、缺陷少，烧结后钨铜合金的组织与性能最优，致密度为96.2%，硬度为235HV，抗弯强度为1 200 MPa，热导率为128 W/(m·K)，电导率为30%IACS。

Effect of copper powders on microstructure and properties of the MIM tungsten-copper alloy

Metal injection molding (MIM) technology was adopted to prepare tungsten-copper alloy. Particle size and particle shape of the selected copper powders was quantitatively characterized by image analysis technology. The influence of the copper powders on the microstructure and properties of MIM tungsten-copper alloy was investigated in detail. By comparing，the characteristic parameters such as particle size, particle size distribution width, aspect ratio, roughness, outgrow and bluntness of the copper powders, the particle sizes of the crushed copper (CCu) powders and the water atomized copper (WCu) powders were much smaller than that of the reduced copper (RCu) powders, however the CCu powders exhibited wider particle size distribution and better regularity, surface smoothness and dispersion microstructure than the WCu powders and RCu powders. With tungsten powder blended with the CCu powders as raw materials, the tungsten-copper green parts were prepared by MIM showed high density and few defects. After sintering, the tungsten-copper alloy has the best microstructure and properties, with a density of 96.2%, a hardness of 235 HV, a bending strength of 1 200 MPa, a thermal conductivity of 128 W/(m·K) and an electrical conductivity of 30%IACS.