Microstructure and Properties of W–Cu Composite/Fe-Based Powder Alloy Vacuum Brazed Joint with Different Filler Metals

Abstract

W–Cu composite and Fe-based powder alloy were brazed with filler metals of Ag–Cu and Cu–Mn–Co alloys in a vacuum furnace. Both of filler metals can join W–Cu composite with Fe-based powder alloy directly in the experiment process. Microstructure, distribution of elements and fracture morphology were observed and analyzed using scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) methods, and phase composition of bonding area was analyzed by X-ray diffraction (XRD). The obtained results indicated that the smooth faying surface and dense microstructure of brazed joint were formed and the primary microstructure of brazing seam were, respectively, Ag(Cu) solid solution and Cu(Mn) solid solution, which ensured forming the stable connection of brazed joint. The bending strength of Ag-based and Cu-based brazed joint can, respectively, reach to 317 and 704 MPa, where fracture showed a typical ductile fracture characteristic. The fracture of Cu-based brazed joint located at brazing seam area, and the fracture of Ag-based brazed joint occurred in Fe-based powder alloy side.

Keywords

• w–cu composite
• microstructure
• element diffusion
• bending strength
• fracture feature