表面织构刀具切削钛合金的基础研究

发布时间：2018-09-14 19:49

【摘要】：钛合金高速切削过程中,刀具的快速磨损严重降低了刀具寿命、切削效率及其加工精度。因此,改善刀-屑界面的摩擦学性能具有重要的现实意义。目前,表面织构刀具的研究表明,表面织构结合一定的润滑条件能够有效地降低切削力、切削温度及刀-屑界面的摩擦系数,这给钛合金切削加工过程中刀具磨损的抑制提供了一条可能的途径。本文选择硬质合金(YG8)和聚晶金刚石(PCD)作为表面织构刀具材料,在干切削和低温MQL条件下,分别开展了微沟槽刀具切削钛合金的基础试验研究。主要研究工作包括:(1)设计了刀具表面微沟槽的形状和参数范围,进行了微沟槽刀具正交切削钛合金的三维有限元建模。为了减少激光加工微沟槽过程中的尺寸误差,提高加工精度,开展了微沟槽刀具制备平台的搭建和研究。(2)通过自行搭建的激光加工试验平台,以YG8和PCD作为刀具材料,研究了光纤激光器的工艺参数对微沟槽加工的影响,通过工艺参数的综合优选,在不同刀具材料表面实现了微沟槽尺寸和形貌的控制。(3)通过正交切削Ti6Al4V钛合金的试验,研究了YG8微沟槽刀具、YG8无沟槽刀具、PCD微沟槽刀具、PCD无沟槽刀具以及YG8刀具表面的微沟槽参数分别在干切削和低温MQL条件下,对切削力、平均摩擦系数和刀具表面抗粘结效果的影响。通过仿真和试验结果,对比分析了干切削条件下微沟槽刀具和无沟槽刀具对刀-屑界面摩擦状况的影响。(4)对比分析了YG8微沟槽刀具和PCD微沟槽刀具切削减摩效果,并从刀-屑接触长度、刀-屑界面润滑膜的形成、刀具表面TiC粘结层的形成等方面探讨和揭示了表面织构刀具的切削作用机理。
[Abstract]:In the process of high speed cutting of titanium alloy, the tool life, cutting efficiency and machining precision are greatly reduced by tool wear. Therefore, it is of great practical significance to improve the tribological properties of the knife-chip interface. At present, the research of surface texture cutting tools shows that surface texture combined with certain lubrication conditions can effectively reduce cutting force, cutting temperature and friction coefficient between cutter and chip. This provides a possible way to restrain tool wear during titanium alloy cutting. In this paper, cemented carbide (YG8) and polycrystalline diamond (PCD) are selected as surface texture cutting materials. The basic experimental study on cutting titanium alloy with micro-groove tool is carried out under the condition of dry cutting and low temperature MQL. The main research work is as follows: (1) the shape and parameter range of the micro-groove on the tool surface are designed, and the three-dimensional finite element model of orthogonal cutting titanium alloy with micro-groove tool is built. In order to reduce the dimension error and improve the machining precision during laser machining, the fabrication platform of micro-groove tool was built and studied. (2) YG8 and PCD were used as tool materials through the self-built laser machining test platform. The influence of the processing parameters of fiber laser on the machining of microgrooves is studied. The size and morphology of the microgrooves are controlled on the surface of different cutting tools by the comprehensive optimization of the process parameters. (3) the experiment of orthogonal cutting of Ti6Al4V titanium alloy is carried out. In this paper, the cutting force of YG8 microgroove cutting tool and YG8 tool surface are studied under dry cutting and low temperature MQL, respectively, under dry cutting condition and low temperature MQL condition. The influence of the average friction coefficient and the anti-bonding effect on the cutting tool surface. Through simulation and test results, the effects of micro-grooves and non-grooves on the friction between micro-grooves and non-grooves are compared and analyzed. (4) the friction reduction effects of YG8 micro-grooves and PCD micro-grooves are compared and analyzed. The cutting mechanism of the surface texture cutting tool is discussed and revealed from the aspects of the contact length of the cutter and chip, the formation of the lubricant film at the knife chip interface, and the formation of the TiC adhesive layer on the surface of the tool.
【学位授予单位】：南京航空航天大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TG146.23;TG711

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