Shape memory effect associated with FCC-HCP martensitic transformation on Co-Al alloys

Abstract

The martensitic transformation and shape memory (SM) effect in Co-Al alloys containing 0-16at%Al were investigated by differential scanning calorimetry (DSC) and bending tests. It was found that the martensitic transformation temperatures decrease and the thermal hystereses increase with increasing Al content. It was also found that an incomplete SM effect occurring in pure Co can be enhanced by the addition of Al over 4 at% and that Co-Al alloys containing Al over 10at% show an excellent SM effect. Co-Al SM alloys possessing high reverse transformation temperatures over 200°C and martensitic transformation in the ferromagnetic state show promise as a new type of SM alloys.