The Effect of Milling Time on Structural, Friction and Wear Behavior of Hot Isostatically Pressed Ti–Ni Alloys for Orthopedic Applications

Abstract

The focus of the present research is to evaluate the effect of milling times (2–48 h) on and tribological behavior of HIPed Ti–Ni. The structural evolution, mechanical properties and tribological behavior of the milled Ti–Ni alloys were evaluated in simulated body fluid (Ringer’s solution at 37 °C), using XRD, SEM and ball-on-disk tribometer. The wear tests were carried out in accordance with the ASTMG 99, ASTM G 133–95 and ISO 7148-1:2012 standards under different applied loads. Experimental results indicated that structural evolution and morphological changes of the milled alloys were sensitive to their milling times. The morphological characterization showed that the crystallite size and the particle size decrease with increasing milling time reaching the lowest values at high milling times. The coefficient of friction and wear rate was lower at high milling time. This improvement is attributed to the closed porosity and grain refinement.