Low-cost (ZrCu)50-xTax high temperature shape memory alloys showing excellent shape memory effect

ZrCu-based alloys, as one of the most potential high-temperature shape memory alloys, show quite high martensitic transformation temperature, relatively low price for the raw materials, and good casting fluidity. In this work, the martensitic transformation (MT) and shape memory effect of (ZrCu)(50-x)Ta-x high-temperature shape memory alloys were systematically investigated. Both X ray diffraction and SEM backscattered electron image demonstrated the coexistence of the main phase monoclinic martensite phase and the second phase Ta2Cu. SEM results also revealed that increasing Ta content resulted in a larger volume fraction of Ta2Cu phase. Differential scanning calorimetry results showed that the MT temperatures remarkably increased with Ta addition. The ductility of the (ZrCu)(50-x)Ta-x alloys was reduced to some degree with increasing Ta content. The shape memory effect was improved significantly, in which (ZrCu)(98)Ta-2 alloy showed the 6.19% maximum recovery strain during 8% pre-strain under compression at 25 degrees C.