Ni/Ti Amed part/substrate interface reconfiguration under electropulsing

The cracks near the interface between the Amed part and substrate due to differences in physical and chemical properties will deteriorate the metallurgical bonding. Here it was found the cracks near the Amed part/substrate interface can be healed using pulsed electric current. Meanwhile, the massive nano-scale NiTi2 precipitates at the interface can be completely dissolved, while the stress concentration was also weakened, which are all beneficial to the metallurgical bonding. During the pulsed treatment, the current distribution around the crack, precipitates and interface is not uniform. The crack tip will produce a high current density zone, where the atomic flow is larger, resulting in the generation of Ti (C, N), so that the crack can be filled. Similarly, due to the presence of a large number of precipitates at the Amed part/substrate interface, the current will also flow around, which will accelerate the dissolution of the precipitates. For the interface stress concentration, the electron wind effect of the pulsed electric current can accelerate the dispersion and annihilation of the dislocation pile-up, and the recrystallization will also be completed quickly.