高体积分数SiCp/Al复合材料具有高比强度、高比模数和良好的耐磨性等优异性能。然而,它们的高硬度和脆性会导致精密制造过程中应力分布更为复杂,这会使材料中产生过大的力和过多的热,从而影响加工精度和工件耐久极限寿命。目的目的通过分析切削过程中颗粒的去除机理和表面缺陷类型,利用纵扭超声辅助铣削(longitudinal-torsionalultrasonicassistedmilling,LTUAM)技术,改善高体积分数SiCp/Al复合材料的加工表面质量。方法方法利用ABAQUS和PYTHON软件,建立考虑颗粒断裂过程的两相随机分布颗粒SiCp/Al复合材料模型,并采用Johnson-Cook模型和BrittleCracking模型对SiCp/Al复合材料纵扭超声辅助铣削过程进行有限元模拟仿真。针对不同加工参数,进行SiCp/Al复合材料纵扭超声辅助铣削和常规铣削(conventionalmilling,CM)试验,评估有限元仿真模拟与试验结果的一致性。结果结果模拟结果表明,损伤和裂纹主要产生在SiC颗粒(SiCp)中上部的切削线上,凹坑缺陷主要产生在颗粒下部的切削线上。试验结果显示,表面缺陷的类型主要包括颗粒的损伤和拔出、颗粒的损伤和断裂形成凹坑、未损伤的颗粒形成凸起、破损颗粒与刀具在已加工表面上挤压摩擦形成犁沟、铝基体涂覆、表面微裂纹和表面空穴等,并且当加工速度120m/min,超声振幅3μm时,最大裂纹深度最小,表面缺陷最小,表面质量最好。结论结论对比有限元仿真结果与试验结果发现,二者的表面质量变化趋势基本具有一致性。纵扭超声辅助铣削技术的应用对提高SiCp/Al复合材料的表面质量有较好效果。

High volume fraction SiCp/Al composites have excellent properties such as high specific strength,high specific modulus and good wear resistance. However,their high hardness and brittleness can lead to complex stress distributions in the precision manufacturing process,which can lead to excessive force and heat and thus affect the accuracy and durability limits. Objectives By analyzing the removal of particles and the types of surface defects in the cutting process,the longitudinal-torsional ultrasonic assisted milling (LTUAM) technology was used to improve the surface quality of high volume fraction SiCp/Al composites. Methods ABAQUS and PYTHON software were used to establish a model of two-phase randomly distributed SiCp/Al composites considering the fracture process of particles. The Johnson-Cook model and the Brittle Cracking model were used to simulate the longitudinal-torsional ultrasonic assisted milling process of SiCp/Al composites using finite element method.For different machining parameters,the longitudinal-torsional ul⁃trasonic assisted milling and conventional milling (CM) tests of SiCp/Al composites were carried out to evaluate the consistency between the finite element simulation and the test results. Results The simulation results showed that the damage and cracks mainly occurred on the cutting line in the middle and upper part of SiC particles,and the pitting defects mainly occured on the cutting line in the lower part of SiC particles.The test results showed that the types of surface defects mainly included particle damage and pulling out,particle damage and fracture forming pits,undamaged particles forming bumps,damaged particles and tools forming furrows on the machined surface by extrusion friction,aluminum matrix coating,surface micro-cracks and surface holes,and so on.Moreover,when the processing speed was 120 m/min and ultrasonic am⁃plitude was 3 μm,the maximum crack depth was the smallest, the surface defect was the smallest and the surface quality was the best. Conclusions Comparing the finite element simulation results with the experi⁃mental results,it was found that the surface quality change trend of the two was basically consistent. The ap⁃plication of longitudinal-torsional ultrasonic assisted milling technology had a good effect on improving the surface quality of SiCp/Al composites.