Machinability improvement of titanium alloys in ultra-precision machining with micro-structured surface
Machinability improvement of titanium alloys in ultra-precision machining with micro-structured surface
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DOI：
10.1177/09544054231191646
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发表时间：
2023-08
期刊：
影响因子：
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通讯作者：
Sujuan Wang;Liangbao Yu;Qin Chao;Zhanwen Sun
中科院分区：
文献类型：
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作者：
Sujuan Wang;Liangbao Yu;Qin Chao;Zhanwen Sun
钛合金以其优异的力学性能在不同领域得到了更广泛的应用。然而，钛合金导热性能差，弹性模数低，刀具磨损率高，是一种难加工材料，尤其是在精密零件的超精密加工中，分段切屑的形成加速了金刚石刀具的磨损。本研究将微结构表面应用于UPM中，通过减少切屑分割引起的切削力波动来改善钛合金在UPM中的加工性。针对Ti6Al4V合金的微结构阵列设计，建立了有限元模型，研究了Ti6Al4V合金正交切削过程中切屑的形成机理和切屑的几何特征。通过车削试验，比较了Ti6Al4V合金在光滑表面和微结构表面进行金刚石车削时的切削力、表面粗糙度和刀具磨损。结果表明，有限元模拟的声表面波芯片与实测值吻合较好。此外，微结构表面有助于减小切削力，减少金刚石刀具磨损，提高钛合金UPM的表面质量。特别是在UPM半精加工过程中，无需任何材料前处理和额外的加工设备，即可在加工表面形成微槽阵列，为高表面质量钛合金零件的高效、可持续UPM加工提供了指导。
Titanium alloys get wider applications in different areas due to its excellent mechanical properties. However, poor thermal conductivity and low elastic module of titanium alloy induce high tool wear and make it being one of hard-to-machine materials; especially the segmented chip formation accelerates the diamond tool wear in ultra-precision machining (UPM) of precision parts. This study applies micro-structured surface to improve machinability of titanium alloys in UPM by reducing the chip segmentation induced cutting forces fluctuations. Finite element (FE) model is built to study chip formation mechanism and characterize geometries of segmented chips in orthogonal diamond cutting of Ti6Al4V alloy with the aims at the design of micro-structures array. Turning experiments are conducted to compare cutting force, surface roughness, and tool wear for diamond turning of Ti6Al4V alloy on smooth surface and micro-structured surface. The results show that the FE simulated saw chips agree well with the measured ones. Moreover, the micro-structured surface helps to decrease cutting force, reduce diamond tool wear, and improve surface quality for UPM of titanium alloy. Especially, the new method fabricates micro-grooves array on the machined surface in half-finishing process of UPM without the need of any material pre-processing and extra manufacturing equipment, which can also provide the guidance for efficient and sustainable UPM of titanium alloys parts with high surface quality.