Influence of braze type on microstructure and mechanical behavior of WC-Co/steel dissimilar joints

This study aims to investigate the influence of different brazing filler alloys on WC-Co/steel joint characteristics. For this purpose, the microstructure and mechanical behavior of the joints were examined. The Cu-Zn-Ni filler alloy produced an alpha + beta microstructure with the highest hardness and shear strength of about 344 MPa. However, the Cu-Zn, BAg-27 and BAg-2a filler alloys had the lowest shear strength of about 203, 177 and 102 MPa, respectively. The microhardness of all the brazed joints near the cemented carbide boundary was greater than that measured near the steel boundary and the middle of the brazing alloy. As a consequence, it was found that the presence of Ni element on the filler alloy can promote the hardness and strength of the joints. The present work provided insight into understanding the microstructure-strength relationship in WC-Co/steel brazing joints, and revealed that choosing proper filler alloys is very effective for improving the joint performance.