Research On Improving Properties Of Materials By Combining Ultrasonic Impact Treatment With Electrospark

A new surface strengthening technology(Ultrasonic Impact Electrical Treatment,UIET)was developed based on ultrasonic impact treatment,and the mechanism of two kinds of UIET(Deposition and Melting)was studied.In addition,how they improved properties of the materials were researched.Firstly in the periphery of the ultrasonic impact equipment a DC power was supplied,so that the circuit was formed between the impact ball of the electrode and the sample.When the ultrasonic impact power was turned on,the ball started vibration;and when the ball hit the specimen,impact of the ball was introduced to the specimen.Then the ball bounced from the specimen,similar to the welding process,the electrical arc and electricspark were produced.At the same time,the micro molten pool was formed on the surface of the specimen and cooled rapidly.After this process repeated,the specimen surface was strengthened to form a full coverage of the UIET layer.Then,the coating was prepared on the surface of the material by UIET with the form of deposition,which was used to explore two different forms of deposition,surface alloying and surface coating.The structure of the material surface,microstructure,composition,were studied,as well as the microhardness and the residual stress field.And then another mechanism of UIET(Melting)was conducted to explore the benefits on the surface properties of the specimen.The surface structure,composition and properties such as hardness,surface roughness and residual stress were analyzed.The excellent effects of UIET on the surface properties were found.Eventually,the effects of UIET melting technology on the performance of the materials was studied.The electrochemical corrosion,friction wear and three point bending fatigue tests were carried out by using matrix sample,ultrasonic impact and UIET samples.The experimental results showed that UIET is superior to the ultrasonic impact technology,which is a kind of excellent methods to improve the performance of the material.