Abstract The premature failure of cutting tools during machining of titanium alloys is primarily attributed to their low thermal conductivity and strain hardening. The coefficient of friction (CoF) at the tool –chip contact depends on the high stress–strain values, interface temperatures, and the velocity of the chip. In this work, a new tribometer is developed to overcome the drawbacks of the existing tribometer and evaluate the adhesive CoF, the heat partition ratio (HPR), and contact pressure. The experiments were conducted on Ti-6Al-4V alloy to estimate the variable CoF and HPR along the rake face. The extent of heat accumulation at the tool–chip interface was quantified using an infrared thermal imaging camera, and the approach successfully mimicked machining conditions, where the tangential force measured up to 900 N and contact pressure was up to 3 GPa. The experiments showed a clear indication of the adhesion of Ti alloy on the tool, strongly suggesting the existence of distinct CoF values for sliding and sticking. The results were further used to develop and validate a finite element model to predict the adhesive CoF, by taking into account the heat partitioning. The results showed considerable dependence of the CoF and HPR on the sliding velocity when implemented in a machining model where 13% maximum error was found in the cutting forces.

中文翻译：

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极端接触条件下粘附摩擦系数的评估及其在加工过程中的应用

摘要 钛合金切削刀具在加工过程中的过早失效主要归因于其低热导率和应变硬化。刀具与切屑接触处的摩擦系数 (CoF) 取决于高应力应变值、界面温度和切屑速度。在这项工作中，开发了一种新的摩擦计来克服现有摩擦计的缺点并评估粘合剂 CoF、热分配比 (HPR) 和接触压力。实验是在 Ti-6Al-4V 合金上进行的，以估计沿前刀面的可变 CoF 和 HPR。使用红外热像仪量化工具 - 切屑界面处的热量积聚程度，该方法成功地模拟了加工条件，其中切向力高达 900 N，接触压力高达 3 GPa。实验清楚地表明了钛合金在工具上的附着力，强烈表明存在不同的滑动和粘附 CoF 值。通过考虑热分配，结果进一步用于开发和验证有限元模型以预测粘合剂 CoF。结果表明，在切削力最大误差为 13% 的加工模型中实施时，CoF 和 HPR 对滑动速度有相当大的依赖性。通过考虑热分配，结果进一步用于开发和验证有限元模型以预测粘合剂 CoF。结果表明，在切削力最大误差为 13% 的加工模型中实施时，CoF 和 HPR 对滑动速度有相当大的依赖性。通过考虑热分配，结果进一步用于开发和验证有限元模型以预测粘合剂 CoF。结果表明，在切削力最大误差为 13% 的加工模型中实施时，CoF 和 HPR 对滑动速度有相当大的依赖性。