Microstructure and mechanical properties of Cu-ZTA cermet prepared by vacuum hot pressing sintering

Abstract

In this paper, seven copper-zirconia toughened alumina (Cu-ZTA) cermets were prepared by vacuum hot pressing sintering (VHP). The effects of different binder content and different particle size of ZTA particles on the mechanical properties of Cu-ZTA cermets were investigated. The microstructure of the composites was studied by x-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. The hardness of the material was measured by micro Vickers hardness tester. The results show that the solid solution strengthening occurs in the hot pressing sintering process, the formation of copper-based solid solution increases the hardness of the matrix, the highest is 192.04 HV _0.1 . The ZTA particles are uniformly distributed in the matrix, and the surface of the ZTA particles is surrounded by a continuous coppermatrix and second phase. Two interfaces are formed between ZTA particles and Cu matrix. One is the ZTA/Cu interface formed by the substitution of Cu atoms for Ni atoms, it is a mechanical meshing interface which extends the service life of cermet under mechanical stress and thermal stress. The other interface is the reaction bonding interface of Cu _3 Ti _3 O and TiO _x . The friction and wear test results show that the use of low-diameter ZTA particles and increasing the content of Cu binder will improve the friction and wear properties of Cu-ZTAcermet. Under the action of stress, the fracture occurs at the interface of Cu/ZTA, and the wear, fracture and extraction of ZTA ceramics cause the failure of Cu-ZTA cermet.

Keywords

• powder metallurgy
• vacuum hot pressing sintering
• cermet
• interface bonding