Abstract This paper describes the wear behavior, subsurface damage mechanism with structural change and indentation creep of bioinert Ti–6Al–4V alloy at different applied loads. Wear test was carried out on a pin-on-disk tribometer and their subsurface damage and deformation mechanism induced by a dry contact sliding were examined by SEM, EBSD and TEM techniques. A microstructural analysis revealed that a very fine β-Ti phase is evenly distributed in the α-Ti matrix. Consequently, the elastic modulus and microhardness of the alloy displayed 107.3 GPa and 324 HV, respectively at room temperature. However, the elastic modulus of Ti-alloy dropped approximately 35.4% at 700 °C. On the other hand, during the pin-on-disk test, severe loose fragments and delamination or plunged groove were observed at the edge of the overall wear tracks, causing abrasive wear. Under a low load, microcracks appeared beneath at the wear track. As increasing the load, the gross plastic deformation and severe microcracks emerged at the worn surface and soften the matrix due to frictional heat, leading to an accelerated wear rate. However, at the worn subsurface recrystallisation phenomena occurred. The grain size reduced and the nanohardness and elastic properties increased.

中文翻译：

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Ti-6Al-4V合金的摩擦学行为：亚表面结构、损伤机制和力学性能

摘要 本文描述了生物惰性 Ti-6Al-4V 合金在不同外加载荷下的磨损行为、亚表面损伤机制与结构变化和压痕蠕变。在针盘式摩擦计上进行磨损试验，并通过扫描电镜、电子束散射和透射电镜技术研究了它们由干接触滑动引起的亚表面损伤和变形机制。显微组织分析表明，极细的 β-Ti 相均匀分布在 α-Ti 基体中。因此，该合金在室温下的弹性模量和显微硬度分别为 107.3 GPa 和 324 HV。然而，钛合金的弹性模量在 700 °C 时下降了约 35.4%。另一方面，在销盘试验过程中，在整体磨损轨迹的边缘观察到严重的松散碎片和分层或陷入凹槽，造成磨损。在低负荷下，磨损轨迹下方出现微裂纹。随着载荷的增加，磨损表面出现粗大的塑性变形和严重的微裂纹，并由于摩擦热而软化基体，导致磨损速度加快。然而，在磨损的表面下发生再结晶现象。晶粒尺寸减小，纳米硬度和弹性性能增加。