Microstructure and mechanical performance of laser additive manufacturing Ni50Ti40Cu10 and Ni45Ti40Cu15 alloy

Abstract Ni-Ti-Cu alloy can not only prevent scale and biological adhesion, but also has applications in aerospace, automotive engineering, and nanotechnology. In this study, Ni50Ti40Cu10 and Ni45Ti40Cu15 alloy large-size thin-walled parts are prepared on the surface of Ti plates using laser additive manufacturing technology. The optimum operational parameters are explored through a two-factor controlled variable method, based on which the effects of TiC and TiB2 addition on the forming quality of Ni50Ti40Cu10 and Ni45Ti40Cu15 alloys are further investigated. SEM, EDS, and other testing methods are used to determine the microstructure composition and distribution, and the composition of the physical phases of the alloy. Finally, tensile and hardness tests are carried out to study the mechanical properties of the alloy. The results show that the better operational parameters for laser additive manufacturing of large-size thin-walled Ni50Ti40Cu10 and Ni45Ti40Cu15 alloys are 1250w laser power and 300 mm min−1 scanning speed. 0.6 wt% TiC addition can achieve better forming quality of the large-size thin-walled parts. The large-size thin-walled Ni50Ti40Cu10 alloy precipitates significantly more Ti2Ni strengthening phases than the large-size thin-walled Ni45Ti40Cu15 alloy. Ni50Ti40Cu10 alloy large-size thin-walled parts have 20% higher tensile strength and 45.4% higher elongation compared to Ni45Ti40Cu15 alloy. The average hardness of Ni45Ti40Cu15 large-size thin-walled parts is 3.4% lower than that of Ni50Ti40Cu10 alloy.