Mechanical properties of highly porous Ti49.5Ni50.5 biomaterials

Ti49.5Ni50.5 shape memory alloy fibers were prepared by a melt overflow process. The martensitic transformation starting temperature of B2 -> B19' in the rapidly solidified fibers was 19 degrees C. Cylindrical billets of Ni-rich Ti-Ni alloy with 75% porosity were produced by a vacuum sintering technology using as-cast alloy fibers. The mechanical properties and shape memory properties of the highly porous Ti-Ni alloy is investigated using a compressive test. The plateau of the stress-strain curve was observed at about 7 MPa and resulted in 8% elongation associated with stress-induced B2 -> B19' transformation. Because of the high porosity of this specimen, the elastic modulus of about 0.95 GPa could be obtained. It was also found that a recovered strain was 5.9% on heating after the compressive deformation. This recovery of the length is ascribed to the shape memory effect which occurs during the martensitic transformation. (C) 2015 Elsevier Ltd. All rights reserved.