基于混合材料模型的颗粒增强钛基复材高速磨削温度研究

Grinding Temperature of Particulate Reinforced Titanium Matrix Composites in High-speed Grinding Based on Multi-material Model

针对颗粒增强钛基复合材料(Particulate reinforced titanium matrix composites, PTMCs)高速磨削加工,建立一种三维混合材料磨削温度场有限元仿真计算模型,既考虑了Ti-6Al-4V基体材料特性,又包含了材料内部的Ti C增强颗粒,由此分析了高速磨削过程中温度场特征及其演变规律。结果表明:基于三维混合材料模型的PTMCs磨削温度预测值与试验值相差小(为8%以下),而基于普通均质材料模型的磨削温度预测值与试验值相差大(为16%以上)。PTMCs工件表面磨削温度随着磨削用量的增加逐渐上升。当砂轮线速度为120 m/s、工件进给速度为6 m/min时,磨削深度从20μm增加到100μm,PTMCs工件表面磨削温度从346℃增加到987℃,温度梯度值从1 070~624℃/mm增加到1 570~1 310℃/mm。磨削温度及其分布梯度对PTMCs亚表层显微组织变化层深度存在显著影响,磨削深度从40μm上升到80μm,显微组织变化层深度从22μm增大到40μm;当磨削深度进一步从80μm增加到100μm时,显微组织变化层深度增加到53μm。

A three-dimension finite element model based on multi-material model is proposed to calculate the grinding temperature in high-speed grinding of particulate reinforced titanium matrix composites(PTMCs). The properties of Ti-6 Al-4 V matrix and Ti C reinforced particles are considered in this model. The grinding temperature and its evolution are analyzed. The results show that the errors of predicted and experimental grinding temperature based on multi-material model are less than 8%, while the errors of predicted and experimental grinding temperature based on traditional homogeneous material model are more than 16%. The grinding temperature of workpiece increases with the increasing of the grinding parameters. In the case of the wheel speed of 120 m/s and the workpiece feed speed of 6 m/min, when the grinding depth increases from 20 μm to 100 μm, the grinding temperature of PTMCs increases from 346 ℃ to 987 ℃, and the temperature gradient values range increases from 1 070-624 ℃/mm to 1 570-1 310 ℃/mm. The grinding temperature and temperature gradient have significant influence on the depth of subsurface microstructure deformation layer. When the grinding depth rises from 40 μm to 80 μm, the depth of microstructure deformation layer increases from 22 μm to 40 μm. When the grinding depth is further increased to 100 μm, the depth of microstructure deformation layer reaches to 53 μm.