2006 Volume 47 Issue 9 Pages 2381-2386
Effects of alloying elements (Si, Ti, V, Cr, Mn, Fe, Ni, Nb, Mo, Ta and W) on γ (fcc)/ε (hcp) martensitic transformation, ductility and shape memory (SM) properties of Co90Al10 alloy were investigated by means of differential scanning calorimetry, X-ray diffraction method, cold-rolling and an SM test. The addition of Ti, V, Mn, Fe, Ni, Nb, Mo, Ta or W decreased the volume fraction of the ε martensite phase (Vm), resulting in improvement of the ductility due to the stabilization of the γ phase, and the addition of Si or Cr, known as hcp stabilizing elements, slightly decreased Vm. The relationship between the martensitic transformation temperatures and Vm was determined in Co-Al and Co-Al-Fe alloys. Co-Al alloys showed behavior different from that of other alloys. The SM effect decreased with decreasing Vm and the Co-Al binary alloys showed the highest SM effect in this study, whereas the transformation temperatures and the ductility could be controlled by the alloying element.