Transformation‐Induced Magnetoelasticity in FeGa Alloys

Global or local phase transformations are commonly used to create or improve useful properties of materials: the functionality of shape memory alloys is enabled by a global thermoelastic transformation. Transformation‐induced plasticity (TRIP) steels and the creation of transformation‐toughened ceramics are examples of materials innovations through local martensitic phase transformations. This research is undertaken to elucidate the nature of the large magnetostriction in FeGa alloys. An investigation of the evolution of the alloy's nanostructure in the varying magnetic fields of the objective lens of an electron microscope reveals the mechanism leading to the large magnetostriction; it is caused by a local martensitic transformation of the DO₃ nanoprecipitates to a 6M phase, leading to transformation‐enhanced magnetoelasticity. The analysis of macroscopic elastic, magnetostriction, and magnetic torque data corroborates this finding.