Shape-memory effect in Co-Ni single crystal

The thermal shape-memory effect at room temperature for Co-32%Ni(mass fraction) magnetic shape memory alloy of single crystal was presented. When compressing the sample along the direction at room temperature, strain can be recovered to some extent during later heating and the recovery rate varies with the pre-strain. But no obvious recoverable strain can be obtained along other crystal directions. For the thermal-mechanical training of the sample along , the recovery strain decreases obviously during the second round of compress and nearly no recovery happens after the third round of compress. A possible mechanism based on reversible motions of Shockley partial dislocations was proposed.