Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7880680 | Acta Materialia | 2015 | 7 Pages |
Abstract
Ferromagnetic Ni-Mn-Ga shape memory alloys with large magnetic-field-induced strains are promising candidates for actuators. Here, we cast replicated Ni-Mn-Ga foams with 57 vol.% of 355-500 μm open pores, with and without directional solidification. The 10M martensitic phase was determined in all foam samples. Directionally solidified foam had a fiber texture, with <1 0 0> closely aligned with the solidification direction. In contrast, foams without directional solidification were more randomly textured. One directionally solidified foam showed a maximum magnetic-field-induced strain of 0.65%, which was twice the value displayed by other foams without directional solidification. This improvement is consistent with a reduction in incompatibility stresses between neighboring grains deforming by twinning, generated by a reduction in crystallographic misorientation in textured foam.
Related Topics
Physical Sciences and Engineering
Materials Science
Ceramics and Composites
Authors
Peiqi Zheng, Nikole J. Kucza, Zilong Wang, Peter Müllner, David C. Dunand,