Abstract Ti-6Al-4 V alloy is a well-acknowledged standard material for the application of modern aerospace, surgical equipment, and prosthetic body parts owing to its stable thermo-physical properties at elevated temperature. However, this structure stability imparts its low thermal conductivity that leads to buildup of heat at tool-workpiece interface during machining which subsequently has a damaging effect on the tool cutting edge. Several biodegradable cutting fluids have already been attempted controlling the heat generation, environmental footprints to improve the overall machinability. In this endeavor, the effectiveness of dry, liquid nitrogen (LN2) and hybrid cryogenic and minimum quantity lubrication (LN2 + MQL) conditions was evaluated in terms of important machinability indicators for instance surface roughness, cutting forces and temperature. The environmental parameters such as total cycle time, productivity, economic analysis, energy consumption and carbon emissions were also analyzed under these cooling conditions. Lastly, the sustainability assessment of process parameters was calculated with the help of the Analytic Hierarchy Process (AHP) coupled with the Technique for Order Preference Based on Similarity to Ideal Solution (TOPSIS) techniques. Findings have exhibited superior cooling/lubrication effect under LN2 + MQL conditions lowering the machining as well as environmental indices. The improvement in cycle time and productivity of LN2 and LN2 + MQL was appeared to be 29.01% and 34.21% as compared with dry turning. The sustainability assessment results also revealed that the lower cutting parameters under LN2 + MQL produced best results to achieve the overall sustainability index.

中文翻译：

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基于生态、经济和技术视角的 Ti-6Al-4 V 合金混合冷却辅助加工可持续性评估

摘要 Ti-6Al-4 V 合金在高温下具有稳定的热物理性能，是现代航空航天、手术设备和假肢等领域公认的标准材料。然而，这种结构稳定性赋予其低热导率，导致加工过程中刀具-工件界面处热量积聚，随后对刀具切削刃产生破坏作用。已经尝试使用几种可生物降解的切削液来控制发热和环境足迹，以提高整体可加工性。在这项工作中，根据重要的可加工性指标（例如表面粗糙度）评估了干燥、液氮 (LN2) 和混合低温和最小量润滑 (LN2 + MQL) 条件的有效性。切削力和温度。在这些冷却条件下，还分析了总循环时间、生产率、经济分析、能源消耗和碳排放等环境参数。最后，在层次分析法 (AHP) 和基于与理想解决方案相似性的订单偏好技术 (TOPSIS) 技术的帮助下，计算了工艺参数的可持续性评估。研究结果表明，在 LN2 + MQL 条件下，具有卓越的冷却/润滑效果，降低了加工和环境指数。与干车削相比，LN2 和 LN2 + MQL 的循环时间和生产率提高了 29.01% 和 34.21%。