Effect of heat treatment on the mechanical properties and microstructure of zirconium-titanium-steel composite plate

Abstract:

In order to obtain better comprehensive performances of Zr/Ti/steel composite plate, the effect of heat treatment on Zr/Ti/steel composite plate was investigated. Based on shear test analysis of titanium-steel interface, the trend that shear strength decreases along with the heat treatment temperature has been found. Besides, the shear strength of vertical to wave direction is higher than that of parallel to wave direction. Based on orthogonal test and variance analysis, it was found out that the significance of heat treatment on shear strength and bonding strength is that: holding temperature > holding time > temperature change rate. The fracture appearance of shear specimen is ductile fracture including local brittle fracture. The heat treatments of 500℃+2h+60℃/h and 540℃+1h+60℃/h are both appropriate heat treatment processes through the analysis of microstructure and micro-hardness on interface. With the holding temperature increasing, the grains become coarsening and the brittle intermetallic compounds-FeTi is formed. The micro-hardness of interface drops along with the increase of heat treatment temperature.

Key words:explosive welding; heat treatment; shear strength; bonding strength; microstructure.