Development of ZrCo-based shape memory and superelastic alloys with a novel type martensite

点击翻译按钮获取中文摘要

The shape memory effect of about 40% and the superelastic strain of 2% were obtained in Zr-Co-X ( X= Ni, Pd, Pt) alloys by convenient bending and tensile tests. This is originated from the formation of martensite with characteristics of both thermal and non-thermal martensitic transformation. A novel long-period stacking-ordered (LPSO) structure of martensite with six layers orthorhombic (6O) structure in ZrCo-based alloys was studied by conventional transmission electron microscopy and high-angle annular dark-field scanning transmission electron microscopy. The lattice parameters of the LPSO structure were estimated to be a = 0.34 nm, b = 0.45 nm, and c = 1.53 nm. The space group of the LPSO structure was determined to be Immm on the basis of the extinction rule and symmetry.