Enhanced Magnetostrain in a ⟨0 0 1⟩A-Textured Ni44.5Co4.9Mn37.5In13.1 Alloy through Superelastic Training

Large magnetostrain can be demonstrated in Ni-Mn-X (X = In, Sn, Sb) meta-magnetic shape memory alloys by resuming the predeformed martensite through magnetic-field-induced reverse martensitic transformation. However, owing to the constraint from the self-accommodated microstructure and randomly distributed crystallographic orientation, spontaneous magnetostrain without predeformation in polycrystalline alloys remains low. Here, by combining microstructure texturing and superelastic training, enhanced spontaneous magnetostrain was achieved in a directionally solidified Ni44.5Co4.9Mn37.5In13.1 alloy with strong <0 0 1>(A) preferred orientation. After superelastic training through cyclic compressive loading/unloading on the directionally solidified alloy, a large spontaneous magnetostrain of similar to 0.65% was obtained by applying a magnetic field of 5 T, showing great improvement when compared to that of the untrained situation, i.e., similar to 0.45%. Such enhanced magnetoresponse is attributed to the internal stress generated through superelastic training, which affects the variant distribution and the resultant output strain in association with the martensitic transformation.

Automated summary

Enhanced spontaneous magnetostrain was achieved in a directionally solidified alloy through microstructure texturing and superelastic training. The study provides an important solution for the application of magnetic shape memory alloys.