Excellent Mechanical Properties and Specific Heat Capacities of Multiphase Er3+xNi Alloys

It is necessary to find alternative regenerator materials for lead because lead is toxic and prohibited in any device by Restriction of Hazardous Substances (RoHS). In this paper, the low temperature heat capacities and mechanical properties of the multiphase Er_3+xNi alloys are studied. The results show that Er_3+xNi alloys consist of Er and Er₃Ni phases. The specific heat capacities of Er_10.819Ni and Er_4.436Ni are higher than lead from 5 to 90 K. The addition of Er makes Er_3+xNi alloys have much more excellent mechanical properties than pure Er₃Ni. The compressive strength of Er_4.436Ni, Er_6.351Ni, and Er_10.819Ni alloys as measured are all more than six times larger than Er₃Ni. And there is a convert from brittle fracture to ductile fracture along with the increase in the content of Er. The study of mechanism of fracture of Er_3+xN_i alloys reveals that the fractures of the alloys are cleavage fracture and quasi-cleavage fracture.