The Manufacture Of TA2/Nicr Explosive Cladding Bar And The Interface Was Researched

The commercial pure (TA2) titanium has good biocompatibility. Nickel chromium alloy (NiCr alloy) have excellent properties of high resistance, high strength, etc. So, the cladding bar of titanium tube outsource nickel chromium alloy bar, will be able to meet the requirements of biocompatibility, heating element, and other functions. So, it can be used in medical field.TA2and NiCr alloy were choosed, and TA2/NiCr cladding bar was manufactured by explosion compound method.The microstructure, properties and related formation mechanism of TA2/NiCr explosion compound on the interface and annealing heat treatment process were investigated by means of OM, SEM, EDS, XRD, EPMA and micro hardness, rockwell hardness and compressive shear strength as well as related analysis and test methods. Finally, the drawing process of TA2/NiCr explosive cladding bar was simulated by the finite element software of Deform-3D.The conclusions were listed as follows:(1)The microstructure of cladding was occurred severe plastic deformation along the direction of detonation. The original equiaxed crystal phase translated into fibrous structure and twin crystals. The microstructure more severe plastic deformation when it nearer the interface. The adiabatic shear bands and melting zone are uneven distribution at the interface. The heat affected zone that consists of coarse grains around the melting zone.(2) The melting zone consists of the "amorphous" atomic configuration of amorphous and orderly structure of the crystal and intermetallic compounds of TiNi and Ti0.98Ni1.02.It has the highest microhardness of800HV0.025.The formation mechanism of amorphous may be together with the high solidification rate of interface, the high pressure and high shear stress.(3) The shear strength tests have shown that TA2/NiCr alloy cladding bar with high bonding strength, about193Mpa. The damage occurred at the interface between combinations, which is may be the existing of melting zone with brittle and stiff, leading to the failure of cladding bar from here.(4)The results show that as the temperature increases, the recovery, recrystallization and grain growth occur, the hardness gradually reduces. Under the annealing of630℃, the deformation microstructure of cladding transformes into fine equiaxial grains. The micro segregation and crack of the melting zone is eliminated basically, component stable, microstructure uniform. There for the annealing temperature of630℃is suitable for the explosive compound bar.(5) Using the theory of uniform diffusion, the problem of the dendrite segregation in the melting zone is eliminated, components tend to stability after short time under630℃is explained successfully.(6) The main parameters of die cone angle and pass condensation are the key factors that effect on the success or failure of drawing. According to the numerical simulation, the cone angle and pass condensation is the best selection in8°～9°and9%～10%during the drawing in each.