Microstructure and shear strength of brazed joints between Ti(C,N)-based cermet and steel with Cu-Ag-Ti filler metal

摘要

Microstructure and shear strength of Ti(C,N)-based cermet/Cu-30Ag-3Ti filler metal/W9Mo3Cr4V steel joints were investigated after brazing in vacuum at 870, 910, and 950 degrees C for 20 min, and 910 degrees C for 10, 20, 30 and 40 min. The reaction layer of Cu-Ni-Ti solid solution between cermet and filler metal was difficult to form during brazing at 870 degrees C, leading to very low shear strength of joints. During brazing at 910 degrees C, Cu-Ni-Ti solid solution was formed between cermet and filler metal, and it became thick with the increase of holding time. Shear strength of joints reached a peak value for 30 min, due to the appropriate thickness of Cu-Ni-Ti solid solution. During brazing at 950 degrees C, Cu-Ni-Ti solid solution was formed and then grew on the whole along with Ag-based solid solution in filler metal, but was not formed between cermet and filler metal, thus deteriorating shear strength of joints. (C) 2016 Published by Elsevier B.V.