High-Temperature Cu-Al-Nb Shape Memory Alloys
摘要
Recently a great interest is focused on shape memory alloys, for high temperature applications. The studied Cu-Al-Nb alloys contain from 0.27 to 7.86 wt % Nb and exhibit the M s temperature of 300 °C. These alloys are characterised by exceptional high plasticity and shape recovery. The reason for that are the particles of primary precipitates distributed in the martensitic matrix which consists of 18R and a few of 2H plates. The relative coarse precipitates of Nb(Cu, Al) 2 and Nb(Cu, At) phases are inherited by the martensite and do not interfere with the thermoelastic reversibility and shape memory. The microstructure of the Nb(Cu,Al) 2 particles is characterised by high stacking faults which is the evidence that they play active role in the process of deforming of those alloys and are responsible for their high plasticity.