부산대학교 도서관

For the bonding couple of S31042 steel and Ni3Al-based superalloy, joint microstructure regulation plays a pivotal role in improving joint performance. Different pretreatment approaches including solution and cold rolling treatments were severally applied to the two substrates before vacuum diffusion bonding. Cold rolling treatment in S31042 steel substrate before bonding promoted the coarsening and precipitation behaviors of large amounts of Z (NbCrN) phases during the bonding process so that the AlN phase decreased in the joint area because of the consumption of N atom in the Z phase. And solution treatment for Ni3Al-based superalloy increased the grain boundary mobility and led to the occurrence of dynamic recrystallization in the diffusion area of the joint by reducing segregation and homogenizing the microstructure within the substrate. As a result, the bonded sample with two substrates that are pretreated exhibited a better tensile strength and elongation at 700 °C.