Evaluation of TZM/ZrC_p-W joint brazed with Ti-35Ni filler: Microstructure and mechanical properties

To broaden the application of the Titanium-Zirconium-Molybdenum alloy (TZM) and the ZrC ceramic particle reinforced tungsten composite (ZrC_p-W) in the elevated temperature fields, the two materials were brazed with Ti-35Ni filler. The interfacial microstructure of the TZM/Ti-35Ni/ZrC_p-W joint was divided into three zones: a reaction zone I containing Mo, Ti-Mo solid solution and Ti₂Ni; a brazing seam II composed of TiNi phase and Ti₂Ni phase; a diffusion layer III consisting of tungsten and (Ti, Zr)C particles fixed by Ti-Ni alloy. With the increase of temperature, in zone I, the micromorphology turned rougher, and the Ti-Mo and Ti-Ni stripes turned more and wider; the brazing seam gradually narrowed and eventually disappeared. A new phase TiC was generated in zone III, and the content of TiC in zone III increased, whereas the content of Ti₂Ni decreased. When brazed at 1260 °C for 10 min, the fracture originated and extended at the TZM side, and the maximum mean shear strengths of 123.8 MPa at room temperature and 110.2 MPa at 800 °C were gained, respectively, the fracture surface were characterized by inter-granular fracture. Meanwhile, the continuous Ti₂Ni phase and the wider Ti-Ni stripes will reduce the joints properties.