A study on microstructure in the brazing interface of WC–TiC–Co hard alloys

Abstract

The brazing parameters and microstructure in the interface of WC–TiC–Co hard alloy and the brazing filler were investigated by means of inside-furnace brazing, scanning electron microscopy (SEM) and X-ray diffraction. Test results indicated that the brazing joint with which the interface combines excellently can be obtained by using Cu–Zn–Ni brazing filler alloy and controlling the heating temperature 940–960 °C, the heat preservation time 10–15 min and a suitable cooling. The crystal microstructure of the brazing filler alloy is α+β eutectic. The interface microstructure of the hard alloy and the brazing filler alloy distribute evenly. The interface zone consists of WC, TiC, CuZn (α-phase). There are no microcracks, inclusions, etc. nearby the interface. The interface zone is formed by mutual diffusion of the hard alloy and the brazing filler alloy under high temperature.