Ruyuan Wang,Chao Zhao,Haolong Liu,Jinbao Long,Xuan Luo,Minghan Sun,Ning Li
TiNi alloys with excellent mechanical properties and unique functional characteristics show substantial potential for producing engineered structural components and biomedical materials. However, the high reactivity of molten TiNi poses significant challenges when ceramic crucibles are used in vacuum induction melting, inevitably resulting in severe ingot contamination. In this study, we report an innovative method for producing high-purity, low-contamination TiNi ingots by using a ZrN/AlN composite ceramic crucible. Fundamentally, this ZrN/AlN composite crucible fabricated with vacuum pressureless sintering technology, is characterized by its high relative density (>95 %) and absence of cracks. The ZrN/AlN composites exhibit impressive properties, including excellent flexural strength, high thermal conductivity, and exceptional thermal shock resistance. Notably, during induction melting, the crucible surface forms a dense TiN barrier layer, thereby protecting the crucible substrate. Compared with traditional oxide refractories, the as-prepared ingots have a low interstitial atom content (Wt. (O, N) < 1000 ppm), demonstrating the superior corrosion resistance of the ZrN/AlN composite crucible. This work provides a comprehensive understanding of crucible-melt interaction mechanisms and a promising method for producing high-purity TiNi alloys.
Gao Xiufeng,Chen Shaoping,Dong Feng,Hu Lifang,Yang Renyao,Wang Wenxian,Munir Zuhair A.
The diffusion bonding between Ti and Ni was investigated in the presence and absence of an imposed electric current. Bonding was carried out over the temperature range of 873–1123 K and the current density range of 255–350 A/cm 2 . The formation and sequence of evolution of the three intermetallic phases, TiNi 3 , TiNi, and Ti 2 Ni, were investigated and discussed in light of calculations of Gibbs free energies of formation and interfacial energies associated with their nucleation. Within the experimental times and in the presence of a current, the growth of the three phases was parabolic. The evolution of the TiNi phase required an incubation period, while the relatively high growth rate of TiNi 3 suggests the possibility of another mechanism. The growth of all phases was enhanced by the application of a direct current, with no apparent dependence on its direction.
危险品化学品经营许可证（带存储）