Effect of heat treatment on bonding characteristics and interfacial microstructures in explosively welded Ti/SUS430 stainless steel clad

Effect of hear treatment on bonding characteristics and interfacial microstructures in explosively welded titanium/SUS430 ferritic stainless steel clad was investigated. The average shear strength of the clad annealed at 1073 K for 3.6 ks was 338 MPa and was equivalent to about 60% of that of an as-welded clad. The strength of the clad annealed at 1073 K gradually decreased to 242 MPa with increasing holding time up to 360 ks. The same tendency was obtained from the clad annealed at 1173 K. On the other hand, the strength of the clad annealed at 1273 K drastically decreased to 107 MPa with increasing holding time up to 360 ks, The clad annealed at 1073 and 1173 K yielded TiC layer at the bonding interface, while the reaction layer in the clad annealed 1273 K consisted of TIG. FeTi. Fr2Ti and chi (Fe29Cr13Ti8) from titanium side. It was noted that chromium existed in the Fe2Ti, which has wide solubility limit for chromium, and chi compounds formed at the SUS430 side. The TiC laver in the former clads acts as a barrier for diffusion of titanium, iron and chromium across the bonding interface and prevents the growth of intermetallic compounds. The clad formed TiC layer at the bonding interface preserved high bonding strength even after prolonged annealing.