Effect of the Welding Thermal Cycle on the Microstructure and Mechanical Properties of TiC Cermet HAZ Using the Gleeble Simulator

Abstract

The effect of heat input on the microstructure and mechanical properties of TiC cermet in MIG welding has been comprehensively investigated by Gleeble simulation. The microstructure, phase composition and shear fracture of TiC cermet were examined by OM (optical microscopy), SEM (scanning electron microscope), TEM (transmission electron microscope) and XRD (X-ray diffraction) analyses. The results show that the heat input has a significant effect on the properties of TiC cermet. With TiC particles and the austenite bonding phase remaining the same, the heat input can effectively improve the toughness of the bonding phase and the structural strength from 219.9 HV0.01 to 380.5 HV0.01 and from 469 MPa to 684 MPa, respectively, as the dislocation density increases while the heat input increases. When the heat input is 3.4 KJ/cm, the shear strength reaches the peak at 684 MPa, with the increase in heat input, the secondary fragmentation of TiC particles increases, and the crack propagation leads to a significant decrease in material strength.