Research on nano-scratching behavior of TiZrHfBeCu(Ni) high entropy bulk metallic glasses

Nanoscratch tests have been conducted to study the tribological behavior of TiZrHfBeCu(Ni) high entropy bulk metallic glasses (HE-BMGs). A classic Zr-based BMG, vit-1 alloy, has been selected as a reference. For all the four adopted alloys, the effect of scratch velocity on the nano-scratch behavior is not obvious. It is found that TiZrHfBeCu(Ni) HE-BMGs possess better nanoscratch resistance than that of vit-1 alloy. Moreover, with the Ni content increasing, the glass transition temperature and hardness increase while the free volume content decreases, resulting in a better nanoscratch resistance. The addition of Ni also changes accumulation mode of the removed chips during the scratching process. Based on the variation of coefficient of friction (COF) during the scratching process, all the four alloys exhibit similar scratching mechanisms, which have been explained in detail. (C) 2019 Elsevier B.V. All rights reserved.