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+x
Ni alloys are studied. The results show that Er
_3+x
Ni alloys consist of Er and Er
₃
Ni phases. The specific heat capacities of Er
_10.819
Ni and Er
_4.436
Ni are higher than lead from 5 to 90 K. The addition of Er makes Er
_3+x
Ni alloys have much more excellent mechanical properties than pure Er
₃
Ni. The compressive strength of Er
_4.436
Ni, Er
_6.351
Ni, and Er
_10.819
Ni alloys as measured are all more than six times larger than Er
₃
Ni. 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+x
N
_i
alloys reveals that the fractures of the alloys are cleavage fracture and quasi-cleavage fracture.