The effect of temperature and dwell time on diamond-WC brazed joint quality using low-melting point active Ag-Cu-In alloy

Abstract

The recent demand for developing micro-pin Diamond grinding tools has gained tremendous importance in tool manufacturing industries. A successful development of these tools requires joining Diamond grits to carbide surface firmly. In this context, the present paper demonstrates the joining of Diamond grits to WC-cermet surface via brazing route using Ag-Cu-24.3In-3Ti active alloy (Incusil-ABA). All brazing experiments were conducted using a resistance type heating furnace under a highly controlled vacuum environment to eliminate contamination. Experimental findings of this investigation indicate that both brazing temperature and dwell time have significant influence on microstructure and other related properties of the alloy. Titanium present in the alloy was found to segregate towards Diamond-alloy interface. It was expected that such segregation would ensure a proper wetting by the alloy. However, the overall morphology of the brazed joint revealed that improper melting and poor wetting by alloy on cermet surface were two major challenges. The current study showcases that a careful control on brazing temperature and dwell time demonstrates a remarkable improvement in wetting characteristics and alloy morphology. It has been observed that a brazing temperature of 780 °C and dwell time of 15 min resulted in a good brazed joint morphology. The study also investigated the effect of said brazing temperature on grits physical characteristics using Raman spectroscopy. At the end, scratch test and wear characteristics of the filler are investigated in detail. The outcome of this investigation will be of immense interest to tool manufacturing industries associated with development of brazed micro-pin Diamond grinding tools using alloys having low melting point.