颗粒增强钛基复合材料磨削试验与仿真研究

Experimental and Simulation Study of Grinding Particle-Reinforced Titanium Matrix Composites

采用单层钎焊CBN砂轮开展了颗粒增强钛基复合材料(PTMCs)磨削试验,对比研究了在磨削TC4钛合金和PTMCs时,磨削用量对磨削力与磨削温度的影响规律,利用有限元仿真研究了PTMCs材料去除演变过程。结果表明,磨削过程中PTMCs的磨削力较TC4增加了15%~30%,磨削温度提高了7%~11%,PTMCs比TC4钛合金更难加工;PTMCs材料去除过程为TC4基体材料的延性去除和Ti C增强颗粒的脆性去除,脆性去除形成了磨削表面孔洞缺陷;当磨削速度从120 m/s降到20 m/s时,磨削表面孔洞缺陷深度由0.8μm增至3.5μm,增加了约3.4倍;提高磨削速度可以降低增强颗粒脆性去除对PTMCs磨削表面孔洞缺陷的影响程度。

In this paper,the experiments on grinding of particle-reinforced titanium matrix composite(PTMCs)were conducted using single-layer brazed CBN wheels.The comparative grinding performance was studied in terms of grinding force and grinding temperature by grinding of PTMCs and TC4 titanium alloy.The evolution process of PTMCs material removal was discussed by the finite element method.The results show that the grinding forces for PTMCs are always 15%–30%higher than that for TC4.The grinding temperature for PTMCs is always 7%–11%higher than that for TC4.PTMCs is more difficult to machine than TC4 titanium alloy.The material removal process of PTMCs includes the ductile removal of TC4 matrix material and the brittle removal of TiC reinforced particles.The hole defect on the grinding surface is created by the brittle removal.When the grinding speed decreases from 120 m/s to 20 m/s,the depth of the hole defect on the ground surface increases from 0.8μm to 3.5μm,an increase of about 3.4 times.The influence of reinforced particle brittle removal on PTMCs ground surface hole defects can be reduced by increasing the grinding speed.