The microstructure evolution and strength mechanism of Ni3(Al, Ti)-type multicomponent alloy with superior mechanical property by laser melting disposition

By introducing nanoscale disordered interfaces into the ordered superlattice grains can achieved a combination of ultra-high strength and excellent ductility in Ni3Al-type high-temperature alloys, but limited by the complex preparation process. In the present work, a Ni3(Al, Ti)-type multicomponent alloy of Ni43.9Co22.4Fe8.8Al10.7Ti11.7B2.5 was successfully fabricated using laser metal deposition (LMD) technique. The microstructural evolution, tensile properties and strengthening mechanism were investigated. Microstructural and phase analyses of the sample reveale the presence of dendritic gamma + gamma ' phases, gamma ' envelopes and interdendritic gamma + gamma ' phases in the alloy. The LMD prepared Ni43.9Co22.4Fe8.8Al10.7Ti11.7B2.5 alloy exhibits superior mechanical property at both room temperature and elevated temperature. Compared to Ni3Al-type intermetallic alloys, the alloy exhibited excellent strength-ductility synergy at room temperature. In addition, the alloy's yield strength rises as temperature rises from 298 K to 973 K, reaching a maximum value of 1043 MPa at 973 K. The strength of the prepared Ni43.9Co22.4Fe8.8Al10.7Ti11.7B2.5 alloy is mainly contributed by lattice friction strengthening, solid solution strengthening, precipitation strengthening and the inherent yield strength of gamma ' envelopes with precipitation strengthening, and the inherent yield strength is the key factor. This work provides insight into the preparation of Ni3(Al, Ti)-type multicomponent alloy with superior mechanical property at both room temperature and elevated temperature by LMD.