Effect of Post Heat Treatment on Bonding Interfaces in Ti/Mild steel/Ti Clad Materials

AbstractTi and Titanium/mild steel/titanium (Ti/MS/Ti) clad materials have been received much attention because of its high specific strength and corrosion-resisting properties compare to those of brass and stainless steels. But, it is difficult to make these materials because brittle intermetallic compound and titanium oxide form during heat treatment. The aim of this study is to get optimized cladding conditions. 1st grade Ti sheets and SPCC mild steel sheets were prepared and then Ti/MS/Ti clad materials were fabricated by cold rolling and post heat treatment process. Microstructure of Ti/MS interfaces was observed by using the SEM and EDX Analyser in order to investigate the effect of post heat treatment on bonding properties of Ti/MS/Ti clad materials. Diffusion bonding was observed at the interfaces of Ti/MS. The Knoop hardness of mild steel decreased with post heat treatment temperature, however, those of Ti decreased at the range of 500∼600°C and showed uniform value till 800°C and then increased rapidly up to 900°C. The Knoop hardness value of diffusion layer showed higher one than those of Ti and mild steel matrices with post heat treated at 600°C. Bonding forces of Ti/Mild steel interfaces were measured by the peel test and those decreased up to 800°C and then increased slightly with post heat treatmen