Refining effect of an intermetallic inoculant on a Cu–Al–Mn shape memory alloy

Cu51Zr14 intermetallic inoculant was adopted to effectively decrease the grain size of a Cu–Al–Mn shape memory alloy (SMA), and key factors affecting the refining effect were systemically investigated. It is found that the important prerequisite for grain refinement of this alloy is that the Cu51Zr14 inoculant can provide effective heterogeneous nucleating centers, and the size of the spherical cap of the Cu–Al–Mn nuclei formed on these centers can reach the critical nucleus radius under a certain undercooling degree. The size of inoculant, the temperature and time of inoculation are all important factors affecting the refining effect. When the Cu51Zr14 inoculant was mechanically crushed into small pieces with the size ranged from 0.05 mm to 1 mm, and the temperature and time of inoculation are 1100 °C and 6 min, respectively, the best refining effect and the highest damping and mechanical properties can be achieved. The correlated mechanisms have been discussed in detail. The results of this work nicely provide an important theoretical base for the research, development as well as application of high damping performance alloys. [Display omitted] •Cu51Zr14 intermetallic inoculant was used to refine the grains of a Cu–Al–Mn SMA•Formation of critical nucleus has strict requirement on size of Cu51Zr14 inoculant•Conditions and mechanisms of high efficiency refinement with inoculant were revealed•After grain refinement, damping and mechanical properties were significantly improved