Fabrication of a β Ti-30Nb-4Sn Biomedical Alloy Using Mechanical Alloying

A beta Ti-30Nb-4Sn weight percentage alloy was fabricated using a powder metallurgy technique consisting of high energy ball milling and consolidation at various temperatures. The initial powdered materials were mixed and milled for 3 and 6 hr. The powders were then compacted and sintered at a temperature of 900-1000 degrees C. It was observed that the titanium was transformed from alpha to beta phase after 6 hr of milling, and the sample sintered at 1000 degrees C contained trace amounts of a titanium. The Vicker's hardness increases as the milling time and sintering temperature increase, the hardness values range from 354 to 386 HV. The hardness contour map using nanoindentation tester indicated that the spatial variation of the hardness values is appeared and the background hardness increases with increasing the milling time in the sintered alloys. The Young's modulus was nearly constant for all sintered Ti-30Nb-4Sn samples at each milling time. The Young's modulus was low (63.93 to 66.4 GPa) compared to the standard alloy, Ti-6Al-4V (103.34 GPa). These samples show enhanced resistance to wear with increased milling times. Additionally, the Ti-30Nb-4Sn alloys have better corrosion properties than the Ti-6Al-4V alloy. All of the samples described herein have improved biocompatibility compared to the standard Ti-6Al-4V alloy ingot, with a decrease in biocompatibility observed at longer milling times.