The Revolutionary Development of Magneto-Superelasticity in Single Crystals

In a recent breakthrough, a research group successfully developed a Ni34Co8Cu8Mn36Ga14 single crystal with a giant magneto-superelasticity of 5%. This advancement was made possible by introducing arrays of ordered dislocations to create preferentially oriented martensitic variants during the magnetically induced reverse martensitic transformation. Unlike traditional elasticity, which typically involves a strain of 0.2% in most metals, superelasticity allows materials to return to their original shape after deformation with strains of several percent.

The collaborative research, led by Prof. Jiang Chengbao and Prof. Wang Jingmin, involved a stress-constrained transition cycling (SCTC) training for the single crystal. By applying compressive stress, ordered dislocations with a specific orientation were introduced to affect the formation of specific martensitic variants during the reversible transformation induced by a magnetic field. Phase field simulations further confirmed the role of internal stress generated by these organized dislocations in shaping the preferred martensitic variants.

The research team also designed a device utilizing a pulsed magnetic field with the single crystal. With a pulse width of 10 ms, the device demonstrated a significant stroke at room temperature due to the giant magneto-superelasticity. It exhibited a rapid response to an 8 ms pulse with a minimal delay of about 0.1 ms. This innovative approach opens up possibilities for the development of new large stroke actuators and efficient energy transducers, enabling contactless material operation.

Prof. Wang highlighted the significance of defect engineering in accessing high-performance functional materials. By combining reversible martensitic transformation with the preferential orientation of martensitic variants, the Ni34Co8Cu8Mn36Ga14 single crystal achieved a remarkable 5% magneto-superelasticity. This pioneering research sets the stage for further advancements in the field of material science and opens up avenues for the creation of cutting-edge technologies based on magneto-superelasticity.