Papers by Author: Alessandra Cremasco

Abstract: The mechanical behavior of β titanium alloys applied as orthopedic biomaterials depends directly on their microstructural features, and can be improved by tailoring the microstructure through the control of their phase transformations. The aim of this investigation is to discuss phase transformations during the aging heat treatment of β Ti-30Nb and β Ti-30Nb-2Sn alloys and to correlate microstructure and mechanical behavior. The results of high temperature XRD experiments showed decomposition of orthorhombic α” phase, followed by the precipitation of ω and α phases. The mechanical behavior of Ti-Nb and Ti-Nb-Sn alloys was found to be highly sensitive to the microstructural changes caused by the addition of Sn and by heat treatments.

Abstract: Titanium alloys form the most versatile class of metallic materials used as biomaterials. Among them it is foreseen that the  type titanium alloy will be a prominent one for orthopedic applications. Aim of the present work was to prepare and characterize a  type titanium alloy containing 35 wt.% Nb. Samples were cooled from the  phase temperatures at different rates. This work includes the effects of heat treatment on the microstructure and hardness, tensile and fatigue properties in air at room temperature. The results showed that microstructure of slow cooled samples are formed by precipitates of  and  phases in a  matrix. After rapid cooling, the microstructure consists of  phase and ” martensite. Mechanical testing showed that the elastic modulus and Vickers hardness of slow cooled samples were significantly higher than that obtained by rapid cooling. On the other hand, it was observed that slow cooled samples showed higher tensile strength and lower ductility. The rapid cooled sample showed fatigue resistance higher than that of slow cooled samples.