AZ31B镁合金功率超声珩磨空化试验研究

空化效应是功率超声珩磨中最常见的现象,为探究空化对被加工材料性能的影响,对表面抛光后的AZ31B镁合金进行超声振动空化实验,采用正交试验研究了超声振幅、与工件距离、超声时间对试件硬度和表面粗糙度的影响,并对试件进行金相组织分析。结果表明:空化可以造成材料表面形貌的改变,并对材料的硬度和表面质量产生变化。影响材料硬度的主要因素依次是超声时间、与工件距离、超声振幅,空化可以将工件硬度提升1. 5-3倍左右,最优参数组合为超声振幅75%、与工件距离1. 0mm、超声时间20min;粗糙度的主要影响因素是与工件距离、超声时间和超声振幅,在超声时间20min、与工件距离2mm、超声振幅50%条件下,试件表面粗糙度Rq值最小,表面质量最好。在硬度最高的试验组条件下,表面晶粒尺寸由15μm减小到2μm左右。因此,超声空化在一定的控制条件下,能明显改善工件的硬度和表面质量,工件硬度的改变与超声空化导致晶粒细化现象有关,试验分析结果对材料改性有现实借鉴意义。

Experimental Study on Power Ultrasonic Honing Cavitation of AZ31B Magnesium Alloy

The cavitation effect is the most common phenomenon in power uhrasonic honing.In order to investigate the effect of cavitation on the properties of the material being processed,Ultrasonic vibration cavitation experiments were carried out on the surface polished AZ31B magnesium alloy.The ultrasonic'amplitude and The influence of workpiece dis- tance and ultrasonic time on the hardness and surface roughness of the test piece.The metallographic analysis of the test piece was then carried out.The results show that cavitation can cause changes in the surface topography of the material and change the hardness and surface quality of the material.The main factors affecting the hardness of the material are ultrasonic time,distance from the workpiece,ultrasonic amplitude,and cavitation can increase the hardness of the workpiece by 1.5 times to 3 times.The optimal parameter set is 75% ultrasonic amplitude,1.0mm distance from the workpiece,and ultrasonic time 20min;The main influencing factors of roughness are the distance from the workpiece,the ultrasonic time and the ultrasonic amplitude.Under the ultrasonic time of 20min,the distance from the workpiece is 2mm,and the ultrasonic amplitude is 50%,the surface roughness Rq of the test piece is the smallest and the surface quality is the best.Under the conditions of the highest hardness test group,the surface grain size decreased from 15μm to about 2μm.Therefore,ultrasonic cavitation can significantly improve the hardness and surface quality of the workpiece under certain control conditions.The change in hardness of the workpiece is related to the phenomenon of grain refinement caused by ultrasonic cavitation.The experimental analysis results have practical reference significance for the modification of materials.