Burst-like shape recovery and caloric effects in Ni-Fe-Ga-Co single crystalline shape memory alloys

摘要

Shape recovery in conventional shape memory alloys is typically a relatively slow process showing low heating rate sensitivity. In contrast to that, some shape memory alloys such as Ni-Fe-Ga-Co, Cu-Al-Ni, Cu-Al-Fe-Mn can exhibit the effect of burst-like shape recovery when the original shape is restored almost instantaneously in a very narrow temperature range. Here we report on an abnormal stress-strain behavior of Ni49Fe18Ga27Co6 single crystals upon uniaxial compression along the [110] axis and caloric effects during burst-like recovery of shape memory strain in the samples. Differential scanning calorimetry (DSC) study revealed that DSC peak shifts to lower temperatures with increasing heating rate.