Abstract: In order to gain a deeper understanding of the cutting processes of particle reinforced aluminum matrix composites, a constitutive model was established based on the strain gradient theory for 45%-SiCp/Al composites through multiphase modeling. Through the secondary development of simulation software ABAQUS, the established constitutive equation and B-W fracture criterion describing fracture were programmed into the user subroutine VUMAT using programming language, and then imported into ABAQUS for simulation analysis. Based on the cutting experiments and simulation analysis results, the changes in surface temperature, internal stress and strain, and dislocations of SiCp/Al composite materials with different cutting depths at the same cutting speed were studied. The results indicate that the modified constitutive model is more consistent with the experimental ones compared to the traditional Johnson-Cook model, and it is found that an increase in cutting depth will trigger a high-temperature gradient. The internal stress of the material will form stress concentration near the particles. A large number of dislocations appear in areas with high strain on the machining surfaces, which increases the difficulty of machining particle reinforced metal matrix composites.

Key words: particle reinforced metal matrix composite, strain gradient, cutting temperature, dislocation

摘要： 为了深入研究颗粒增强铝基复合材料的切削过程，对45%体积分数的SiCp/Al复合材料通过多相建模的方法建立了基于应变梯度的本构模型，并对软件ABAQUS进行了二次开发，用程序语言将所建本构模型以及描述断裂的B-W断裂准则编入用户子程序VUMAT，并导入ABAQUS进行仿真分析。结合切削实验和仿真分析结果，研究了在相同切削速度及不同切削深度下SiCp/Al复合材料加工表面温度、材料内部应力应变和位错的变化情况。研究结果表明，相较于传统Johnson-Cook模型，修正后的本构模型所得到的结果与实验结果更加吻合；切削深度增大会引发高温梯度；材料内部应力会在颗粒附近形成应力集中；在加工表面应变较大的区域出现大量位错，导致加工颗粒增强金属基复合材料的难度上升。

关键词: 颗粒增强金属基复合材料, 应变梯度, 切削温度, 位错