Fe2O3在钛合金干滑动磨损及摩擦层形成中的作用

Role of Fe2O3 in Dry Sliding Wear of A Titanium Alloy and Formation of Tribo-Layers

摘要:

通过在Ti6Al4V合金滑动界面人工添加Fe₂O₃纳米颗粒及其与TiO₂、MoS₂的混合物,试图人工诱导含Fe₂O₃摩擦层在室温下的快速形成；研究了Fe₂O₃、TiO₂、MoS₂在钛合金滑动过程中的作用,并探讨Fe₂O₃相对含量对钛合金磨损行为及磨损机制的影响。结果表明：干滑动下的Ti6Al4V合金耐磨性较差,磨面添加的TiO₂进一步加速磨损,MoS₂一定程度上降低了磨损但并不显著,而Fe₂O₃完全抑制磨损但增大了摩擦系数。高载下,富TiO₂、MoS₂颗粒并不能形成摩擦层,反而聚集在磨面犁沟或者凹坑处,而富Fe₂O₃则容易形成致密的摩擦层覆盖于磨损表面,这证实了钛合金高温耐磨性的改善是由于Fe₂O₃的出现。混合MoS₂+80wt.% Fe₂O₃形成的摩擦层,兼具MoS₂的润滑性和Fe₂O₃的承载能力,给Ti6Al4V合金带来最佳的摩擦磨损性能。

Abstract:

Artificial tribo-layer containing Fe₂O₃ were induced to form at room temperature by supplying Fe₂O₃ nanoparticles and its mixtures with TiO₂ or MoS₂ onto the sliding interfaces of Ti6Al4V alloy and GCr15 steel. The role of Fe₂O₃, TiO₂ and MoS₂ on the sliding wear performance of Ti6Al4V alloy was respectively studied. The effect of the relative content of Fe₂O₃ in artificial tribo-layer on wear behavior and mechanism of Ti6Al4V alloy was also explored. Results showed that Ti6Al4V alloy indeed presented a terrible wear resistance, but it would be changed by the supplied particles. The wear rate of Ti6Al4V alloy was further accelerated by TiO₂, was slightly and inappreciably reduced by MoS₂, but was completely inhibited by Fe₂O₃. In the case of supplying TiO₂-rich or MoS₂-rich particles, they were agglomerated into the grooves or pits on worn surfaces, instead of forming a tribo-layer. For Fe₂O₃-rich particles, an artificial tribo-layer were noticed to form and cover the worn surfaces. It was confirmed that the improved elevated-temperature wear resistance of titanium alloy was attributed to the appearance of Fe₂O₃. As the particles of MoS₂+80wt.% Fe₂O₃ were supplied, the tribo-layer possessed both of the lubricating property of MoS₂ and the load-carrying ability from Fe₂O₃, which brought the best performance of friction and wear for Ti6Al4V alloy.