Microscopic Formation Mechanism and Physical Properties of Mo/Cu Composites with High Densification

Abstract

The formation mechanism and physical properties of high-densification Mo/Cu composites are studied by analyzing materials' microstructure, atom diffusion near the phase interface and physical properties. In the liquid phase sintering, the atomic diffusion occurs at the interface of molybdenum and copper, mainly the diffusion of copper atoms into molybdenum phase. Copper atoms in the material diffuse into the molybdenum phase to form a micron sized Cu-Mo solid solution, and no compound phase is found in the material structure, which forms a good interface bonding effect and makes it have high densification. The average linear expansion coefficients, thermal conductivities, electrical conductivities and tensile strengths of high-densification Mo/Cu composites with different copper content are linearly correlated with copper content. Mo80Cu20 is organized as a connected molybdenum skeleton and a small amount of copper phase in the voids. The tensile fracture of Mo80Cu20 is mainly exhibited as brittle fracture of the sintering neck of the molybdenum phase. The copper phase in Mo70Cu30, Mo60Cu40 or Mo50Cu50 is in a connected state, with plasticity significantly increased. Under the action of tensile stress, the ductile fracture of copper phase and the brittle fracture of sintering neck of the molybdenum phase occur simultaneously in these materials.