Experimental and numerical investigation of microstructure and evolution of TiNi Alloy/Q235 steel interfaces prepared by explosive welding

This work presents a systematic study of microstructure and mechanical property of TiNi Alloy/Q235 steel explosive-welded interface. The structure evolution as well as the thermodynamic state during the welding process was simulated using Smoothed Particle Hydrodynamic (SPH) numerical method. The interface is featured by regular wave structure with a period of similar to 400 mu m and an amplitude of similar to 120 mu m, resulting from the periodic interaction process of jets and colliding plates. Furthermore, it was found that the waves do not form in the initial collision zone, but undergo an evolutionary process of straight irregular small wave-steady wave transformation. Intermetallic compounds like Fe2Ti and Ni3Ti were found in melting zones, which are the source of the microscopic cracks. Even so, the interface exhibits good bonding strength of 291 MPa that is higher than the Q235 steel of 180 MPa. The nanoindentation results show the hardness values decrease at first and then increase to the initial value with increasing distance from the bonding interface. The melting zone exhibits an ultrahigh hardness of 11.06 GPa, which confirms the formation of brittle intermetallic in the melting zone. (c) 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

This study systematically examines the microstructure and mechanical properties of the TiNi Alloy/Q235 steel explosive-welded interface. The interface features a regular wave structure and the presence of intermetallic compounds, leading to good bonding strength but also microscopic cracks. Additionally, nanoindentation results show varying hardness values across the interface.