Interfacial bonding and strength of tungsten to copper or its alloy joints with Ti foil and Ti/Ni/Ti multiple interlayers

Ti foil and Ti/Ni/Ti multiple interlayers were selected for the bonding of tungsten to copper or CuCrZr alloy with thermal-mechanical simulator Gleeble 1500D. The effects of technology parameters on the microstructures and shear strength of the joints were performed. The interfacial bonding mechanism was studied through microanalysis. When Ti foil was used for bonding of tungsten to pure copper but not transformed into liquid solution during the holding time, a reaction zone including multiple compound layers with brittleness was formed and the strength of the joints was lower. However, if the Ti foil was transformed into liquid solution and extruded mostly out of the bonding zone, the strength of the joints can reach 220MPa due to the chemical and mechanical interfacial bonding. The joint was formed through the diffusion and reaction among the Ti, Ni, Cu and W to form multiple compound layers and solid solution layers when Ti/Ni/Ti was used for bonding tungsten to CuCrZr alloy. Similarly, if Ti foil was transformed into liquid solution, a strong joint can be obtained, otherwise, the strength was relatively low.