2022 Volume 6 Issue 1 Pages 15-19
As a novel method of vibration power generation, we propose a mechanism that utilizes the stress-induced phase transformation of ferromagnetic superelastic alloys. Since the parent phase of Fe-Mn-Al-Ni alloy is ferromagnetic and the martensite phase is antiferromagnetic, there is a possibility that the magnetic changes associated with phase transformation can be converted into electric power by electromagnetic induction. Therefore, the characteristics of Fe-Mn-Al-Ni alloy were measured with and without stress. It was confirmed that the magnetic flux density decreased when a compressive stress of about 450 MPa was applied to the sample but returned to the original state by unloading. In the observed microstructure, martensite appeared when a compressive stress of about 450 MPa was applied to the parent phase, but disappeared when unloaded, and a reversible change confirmed that the phase returned to the parent phase again. An analysis of the martensite phase fraction revealed that a magnetization change was obtained in accordance with the phase fraction. EBSD measurements also identified the crystal structure as bcc in the parent phase and fcc for the surface undulations caused by strain. From these results, it was clarified that the phase transformation occurs due to stress.
