生体用 β 型 Ti-Nb-Ta-Zr 系合金の大気および擬似生体内環境中における摩擦摩耗特性に及ぼす熱処理および荷重の影響

Abstract

The frictional wear characteristics of heat-treated Ti-29Nb-13Ta-4.6Zr (TNTZ) subjected to solution treatment (TNTZST) or aging treatments at 598, 673, and 723 K, respectively after solution treatment (TNTZ598 K, TNTZ673 K, and TNTZ723 K, respectively) and Ti-6Al-4V ELI (Ti64) subjected to aging treatment after solution treatment (T64STA) in air and simulated body environment (Ringer's solution) were investigated as a function of load in this study. Wear weight losses of TNTZST, TNTZ598 K, TNTZ673 K, TNTZ723 K, and Ti64STA are smaller in Ringer's solution than in air under both low and high loading conditions (1.96 and 29.4 N, respectively). This is considered to suggest that the frictional coefficient decreased because of the lubricant effect of Ringer's solution between the contact surfaces of specimen and zirconia ball as mating material. The wear losses of TNTZST, TNTZ598 K, TNTZ673 K, TNTZ723 K, and Ti64STA increase with increasing load in Ringer's solution. The wear losses of TNTZST, TNTZ598 K, TNTZ673 K, and TNTZ723 K at a low loading level are smaller than that of Ti64STA in Ringer's solution. On the other hand, the wear losses of TNTZ598 K and TNTZ673 K at a high loading level are larger than that of Ti64STA in Ringer's solution. This reason is that the transition point from sever wear to mild wear versus load is changed according to the materials.