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The Ti–Ni–Sn phase in Ti–(50-2X)Ni–XSn (X =5, 8, 10, 12.5) alloys showed the B2–R–B19′ martensitic transformation on cooling and the B19′–B2 transformation on heating. The B2–R transformation start temperature (T R) decreased from 314 to 303K with increasing Sn content from 5 to 12.5at.%. Ti–(50-2X)Ni–XSn alloys with X less than 12.5at.% were deformed in a plastic manner up to more than 6%. The shape recovery ratio was about 95% after training, although it was less than 81% before training. [ABSTRACT FROM AUTHOR]

Abstract: This study investigated the surface characteristics and in vitro biocompatibility of a titanium (Ti) oxide layer incorporating calcium ions (Ca) obtained by hydrothermal treatment with or without post heat-treatment in the Ti–13Nb–13Zr alloy. The surface characteristics were evaluated by scanning electron microscopy, thin-film X-ray diffractometry, X-ray photoelectron spectroscopy, atomic force microscopy and contact angle measurements. In vitro biocompatibility of the Ca-containing surfaces was assessed in comparison with untreated surfaces using a pre-osteoblast cell line. Hydrothermal treatment produced a crystalline CaTiO3 layer. Post heat-treatment at 400°C for 2h in air significantly decreased water contact angles in the CaTiO3 layer (p <0.001). The Ca-incorporated alloy surfaces displayed markedly increased cell viability and ALP activity compared with untreated surfaces (p <0.001), and also an upregulated expression of various integrin genes (α1, α2, α5, αv, β1 and β3) at an early incubation time-point. Post heat-treatment further increased attachment and ALP activity in cells grown on Ca-incorporated Ti–13Nb–13Zr alloy surfaces. The results indicate that the Ca-incorporated oxide layer produced by hydrothermal treatment and a simple post heat-treatment may be effective in improving bone healing in Ti–13Nb–13Zr alloy implants by enhancing the viability and differentiation of osteoblastic cells. [Copyright &y& Elsevier]