Structure of rapidly quenched Ga-free Heusler alloys

Abstract

The development of magnetic shape memory alloys in ribbon form is a new field with interesting thermo-elastic and thermo-magnetic properties. In this work, two Ga-free Heusler alloys were obtained. It is found that is possible to obtain these materials with an austenite structure or with a martensite structure at room temperature. The lattice parameters are a = 0.5985(4) nm for the cubic L2 1 austenite and a = 1.2604(5) nm, b = 0.4925(2) nm and c = 0.4775(9) nm for the orthorhombic martensite. Furthermore, the microstructure followed by scanning electron microscopy confirms the coexistence of equiaxial and columnar grains with an inhomogeneous distribution. The composition of each alloy is homogeneous. The control of different parameters, as the composition and the processing conditions can be a good option in order to obtain a material with the crystalline structure and the microstructure desired at room or near room temperature. This fact, can favours the applicability of this materials