Mechanically enhancing a brazed joint of WC-Co/3Cr13 by utilizing a nanoporous Cu lamina interlayer prepared by chemical dealloying

Abstract

Ag-Cu-Ti brazing alloys may allow sound joining between WC-Co cemented carbide (YG20) and 3Cr13 stainless steel. However, the issue of excessive formation of agglomerated brittle Cu-Ti compounds in the joint seam, which deteriorates mechanical performance, is still a major processing drawback. Here, a nanoporous copper (NP-Cu) lamina, prepared by chemically dealloying an Mg67Cu33 (at. %) alloy precursor, was used as an interlayer for assisting the brazing process between YG20 alloy and 3Cr13 stainless steel. The effect of introducing the NP-Cu interlayer on the microstructure and mechanical properties of the joints was investigated. Results revealed that the Cu-Ti compounds in the brazing seam acquired reduced size and dispersed distribution by applying the NP-Cu interlayer. The technique outperforms the directly brazed alternative, with a shear strength increase of 70%. The interlayer contributed by its high specific surface and excellent surface metallurgical activity, overcoming the drawback of agglomerated Cu-Ti compound development. The new technique allows a process based microstructural and chemical control, with vast potential applications in the joining of WC-Co cemented carbide and stainless-steel materials.