摘要
目的揭示高体积分数SiC_(p)/Al复合材料在超声辅助加工条件下的材料去除机理。方法采用SiC_(p)/Al复合材料的超声辅助划切试验,探究划切参数变化对超声振幅、划切力及摩擦因数的影响规律,并通过扫描电子显微镜和激光共聚焦显微镜对划痕表面微观形貌进行观察,分析单点金刚石磨粒工具超声辅助划切材料去除的特点。结果随着划切深度从0.01 mm增加到0.05 mm,电流值逐渐降低,电流值变化量从12 mA增加到25 mA,超声振幅逐渐衰减,金刚石压头的轴向冲击作用减弱。划切深度和划切速度的增加使切向挤压切削作用增强,划切力和摩擦因数增大。在材料去除过程中,碳化硅颗粒存在破碎成小颗粒、剪切断裂破碎和拔出等多种去除形式,铝基体出现明显的塑性流动和涂覆现象,并形成切削沟槽外侧堆积。结论当切削深度和进给速度较小时,材料去除主要是在轴向的高频振动冲击作用下完成,材料表面加工质量较好;当切削深度和进给速度逐渐增大时,材料去除是在轴向冲击破碎和切向挤压切削共同作用下完成,材料表面加工质量逐渐降低。
The material removal mechanism of the high-volume fraction SiC_(p)/Al composites in ultrasonic assisted machining was elucidated by ultrasonic assisted scratch experiment.The influence of scratching parameters on the ultrasonic amplitude,scratching force and friction coefficient were investigated by the experiment.The morphology of the scratch grooves was observed with the scanning electron microscope and the laser confocal microscopy.Further,the characteristics of ultrasonic assisted machining was analyzed by ultrasonic assisted scratch experimental date.The experimental results show that the current value decreases gradually with the increase of scratching depth from 0.01 mm to 0.05 mm,the change amount of current value raises from 12 mA to 25 mA,the ultrasonic amplitude decreases gradually,the axial impact of diamond indenter weakens;the extrusion cutting effect of tangential direction is enhanced with the increase of scratching depth and scratching speed,the scratching force and friction coefficient are improved.During the process of scratch,the SiC particles are broken into small particles,sheared fracture and some SiC particles are pulled out.The aluminum matrix appears obvious plastic flow and coating phenomenon,forming the accumulation outside the scratch grooves.Thus,when the cutting depth and feed speed are small,the material removal is mainly completed by the action of axial high-frequency vibration impact,the quality of the machining surface is higher;when the cutting depth and feed speed gradually increase,the material removal is completed by the combined action of axial impact crushing and tangential extrusion cutting,the quality of machining surface is gradually worse.
作者
张红哲
朱晓春
鲍永杰
ZHANG Hong-zhe;ZHU Xiao-chun;BAO Yong-jie(Engineering Training Center,Dalian University of Technology,Liaoning Dalian 116023,China;Marine Engineering College,Dalian Maritime University,Liaoning Dalian 116026,China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2022年第6期327-335,363,共10页
Surface Technology
基金
国家自然科学基金(51875079)
辽宁省兴辽英才计划(XLYC1907196)
国家自然基金联合基金(U1908228)。
