A novel route for growing single-crystal and internal-stress-induced martensitic transformation of ferromagnetic shape memory alloys Co_(50)Ni_(20)Ga_(30)

摘要

As a new single-crystal preparation method, undercooling directional solidification has been proposed for the case of the ferromagnetic shape memory Co_(50)Ni_(20)Ga_(30) rod. The as-grown single crystal has strong [111] orientation and a very homogenous composition along the rod axis, which confirms that the undercooling directional solidification is a feasible and effective approach for preparing Co-Ni-Ga single crystals. Additionally, the drastically increased transformation temperatures upon undercooling was ascribed to the internal stress induced martensitic transformation.