Effect of microwave sintering time and homogenization treatment on biomedical Ti-51%Ni SMAs

Abstract

Objective: The influence of microwave sintering time and Homogenization Treatment (HT) on the microstructure, density, phase composition, mechanical properties and phase transformation temperatures of biocompatible Ti-51%Ni Shape Memory Alloys (SMAs) are determined. Methods/Statistical Analysis: These alloys are fabricated at 900°C for two different sintering times such as 5 min. and 30 min. Findings: The Field Emission Scanning Electron Microscopy (FESEM) micrographs show microstructure of needle-like morphology except for the sample which sintered at 900°C for 30 min. without HT. Applications/Improvements: Sample synthesized at 900°C for 30 min. without HT revealed the highest performance in terms of maximum compressive strength (1376 MPa) at 29% strain, Austenite finish temperature (Af) of 27°C and Martensite finish temperature (Mf) of 47°C at 18% porosity. They showed the Af temperature very close to the human body temperature, thus prospective for biomedical applications. During heating, the Differential Scanning Calorimeter (DSC) baseline shows multi-endothermic peaks, while during the cooling process there is only one exothermic peak.