Transformation behaviour of Ti–Ni and Ti–Ni–Cu alloy ribbons with nano Ti₂Ni particles

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P><P>Ti–Ni and Ti–Ni–Cu alloy ribbons have been prepared by single roll melt spinning, and then martensitic transformation behaviours were investigated by means of transmission electron microscopy, differential scanning calorimetry and X-ray diffraction. In 51Ti–49Ni(at.%) alloy ribbons, Ti<SUB>2</SUB>Ni particles of a size less than 50nm with the coherent interface with the matrix were found, while they were not found in 50Ti–50Ni alloy ribbons. In 49Ti–46Ni–5Cu and 50Ti–45Ni–5Cu alloy ribbons, Ti<SUB>2</SUB>Ni particles of size less than 30nm with coherent interface with the matrix were found. Coherent Ti<SUB>2</SUB>Ni particles induced the R phase transformation in Ti–Ni alloys, and consequently transformation occurred in two-stages, i.e., B2–R–B19. Coherent Ti<SUB>2</SUB>Ni particles induced the B19 martensite in a Ti–45Ni–5Cu alloy, and consequently transformation occurred in two-stages, i.e., B2–B19–B19′. The change in transformation behaviour was ascribed to strain fields developed around coherent Ti<SUB>2</SUB>Ni particles.</P>