钨合金超声椭圆振动切削表面完整性研究

Study on Surface Integrity of Tungsten Alloy Processed by Ultrasonic Elliptical Vibration Cutting

目的研究钨合金超声椭圆振动切削表面完整性的变化规律,为实现钨合金高表面完整性加工提供理论基础。方法设计单因素试验,采用单晶金刚石刀具开展钨合金超声椭圆振动切削试验,并与普通切削进行对比,研究不同切削深度下超声椭圆振动对工件表面形貌、表面粗糙度、微观组织、位错密度、显微硬度以及表面残余应力的影响。结果普通切削或超声椭圆振动切削后,工件表面的位错密度、显微硬度以及残余应力均随着切削深度的增加而增大,且亚表面的晶粒都发生了一定程度的塑性变形,并出现了晶粒细化。与普通切削相比,超声椭圆振动切削可以有效抑制加工过程中鳞刺和犁沟的产生,改善表面粗糙度;工件表面会产生更高的硬化程度、残余压应力和位错密度,位错密度的量级在10^(8) mm^(–2);亚表面的变质层厚度更小。结论相比于普通切削,超声椭圆振动切削可以降低表面粗糙度,增大表面残余压应力,提高工件表面完整性。

The work aims to study the variation law of surface integrity of ultrasonic elliptical vibration cutting of tungsten alloy and provide a theoretical basis for the processing of tungsten alloy with a high surface integrity.Single-factor tests were designed to carry out ultrasonic elliptical vibration cutting tests on tungsten alloys using single-crystal diamond tools and compared with ordinary cutting to investigate the effects of ultrasonic elliptical vibration on the surface morphology,surface roughness,microstructure,dislocation density,microhardness and surface residual stress of the workpiece at different depths of cut.Whether using conventional cutting or ultrasonic elliptical vibration cutting,the surface dislocation density,microhardness,and residual stress of the workpiece were all increased with the depth of cut increasing and the workpiece will experience large strain and high strain rate,which would lead to a certain degree of plastic deformation and grain refinement.Compared with conventional cutting,ultrasonic elliptical vibration cutting could effectively suppress the generation of scaly spines and furrows due to the intermittent contact characteristic between the tool and the workpiece and reduce the surface roughness.Moreover,the surface hardening and residual compressive stress of the workpiece processed by ultrasonic elliptical vibration cutting were higher.And the dislocations in the tungsten phase and the bonding phase were with the higher dislocation density,which was on the order of 10^(8) mm^(-2).In addition,the workpiece,which processed by ultrasonic elliptical vibration cutting,generated less.Compared with conventional cutting,ultrasonic elliptical vibration cutting can decrease surface roughness surface quality,increase the surface residual compressive stress and improve the surface integrity of the tungsten alloy workpiece.