(TiZrNbTa)_(90)Mo_(10)高熵合金与Al_(2)O_(3)干摩擦条件下的滑动磨损行为

Dry-Sliding Wear Behavior of(TiZrNbTa)Mo HighEntropy Alloy Against AlO

采用"球-板"式往复滑动方式,研究了电弧熔炼态bcc结构(TiZrNbTa)_(90)Mo_(10)高熵合金与Al_(2)O_(3)球在干摩擦条件下的摩擦磨损行为,并与Ti6Al4V和Co28Cr6Mo 2种合金进行了对比。通过对磨痕、磨屑、磨球表面形貌的表征,揭示出该高熵合金在摩擦学和磨损机制上的特征。结果表明,(TiZrNbTa)_(90)Mo_(10)高熵合金与Al_(2)O_(3)干滑动摩擦的摩擦系数(f)为0.8~0.9,约是同条件下Ti6Al4V和Co28Cr6Mo合金与Al_(2)O_(3)摩擦体系的2倍。(TiZrNbTa)_(90)Mo_(10)高熵合金的比磨损率约是Ti6Al4V合金的2.3倍,是Co28Cr6Mo合金的90倍,即耐磨性不如后2种合金;其磨损机制因施加载荷的大小而异,低载荷下以磨粒磨损为主,高载荷下三体磨粒磨损的作用愈显突出,在磨损机制上明显不同于Ti6Al4V和Co28Cr6Mo。该高熵合金在高强度和高硬度上的优势并未保证其拥有良好的耐磨性,与之相适宜的低摩擦磨损对磨副材料仍有待于进一步研究。

Degenerative and inflammatory joint disease including osteoarthritis,rheumatoid arthritis and chondromalacia affect more and more people.The standard treatment nowadays is arthroplasty,such as total hip replacement(THR).The material selection for the combination of bearing surfaces is a critical issue to determine the life quality of patients with THR.High entropy alloy(HEA)is expected to be a candidate material owing to its appreciated mechanical properties.A new HEA,(TiZrNbTa)_(90)Mo_(10)alloy was developed recently,but its tribological behavior is still unclear.Using ball-on-plate reciprocating sliding approach,dry sliding wear behavior of arc-melted(TiZrNbTa)_(90)Mo_(10)HEA against Al_(2)O_(3)was investigated,together with two conventional implant alloys,Ti6 Al4 V and Co28 Cr6 Mo,for comparison.The wear mechanism of these alloys was revealed by characterizing the morphology of worn track,wear debris and scar on counterpart ball.It was shown that,under dry sliding condition,the coefficient of friction(f)of the HEA was determined to be 0.8~0.9,which is nearly double of that of either Ti6 Al4 V or Co28 Cr6 Mo,and is insensitive to the applied loading.Meanwhile,specific wear rate of this HEA is approximately 2.3 and 90 times of that of Ti6 Al4 V and Co28 Cr6 Mo,respectively,which means that wear resistance of the former is inferior to the two latter under the current conditions.As indicated,wear mechanism of the HEA is dependent on the applied loading.The abrasive wear is predominant under lower-level loading,whereas the third-body abrasive wear took place and played a remarkable role as the loading increased.It is noteworthy that such a complex mechanism is considerably different from that of either Ti6 Al4 V or Co28 Cr6 Mo.Furthermore,it is of interest to note that the advantage in mechanical properties of the current HEA,such as high strength and high hardness,is not necessarily to offer its excellent wear resistance,at least under the current tribological condition.It is proposed as future work to screen the appreciate materials as counterpart for this HEA and to characterize its wear behavior under a condition containing lubricant medium such as physiological fluid.