Research On Control Of Diamond Drift Behavior And Interfacial Bonding Characteristics In Ultrasonic Assisted Laser Brazing Of Diamond Grains

Diamond tools prepared by high-temperature brazing are widely used in industrial production due to their excellent properties.At present,the methods for preparing diamond tools by high-temperature brazing are mainly divided into three types:vacuum brazing,induction brazing and laser brazing.As an emerging diamond tool processing method,laser brazing has the advantages of high processing efficiency and good processing flexibility,and has been favored by many scholars.In this paper,a high-speed camera is used to observe the process of ultrasonic-assisted laser brazing of diamond,and the drift behavior of diamond is adjusted by coating an active agent on the cladding layer.The effect of ultrasound on the surface formation of the brazing layer,the structure of the interface between the diamond and the solder,and the distribution of interface elements were studied.The mechanism of the combination of diamond and solder under the assistance of ultrasound was analyzed,and the effect of ultrasound on the bonding strength between the solder and diamond was researched.The main works of this paper as following:(1)A diamond paraxial jetting device has been designed,which sprays diamond into the molten pool by paraxial jetting.The effects of welding position,ultrasonic wave,diamond drop position and active agent on the flow behavior of diamond in the molten pool were studied.The test results show that after the process of spraying diamond on the side axis,there is no agglomeration of diamond on the brazing layer.The flow behavior of diamond in the molten pool during flat welding is related to the flow direction of the molten pool,and the flow behavior of diamond during flat welding is related to the position of the diamond sprayed by the side axis.Ultrasound has no obvious effect on the flow behavior of diamond in the molten pool,but it is of great significance for improving the surface quality of the brazing layer.In the diamond specimens prepared by active laser brazing of diamond,the diamond particles are all distributed in the center of the brazing layer.(2)The effect of ultrasound on active laser brazing of diamond was carried out,and the interface bonding mechanism between diamond and solder under ultrasound was analyzed.The research results show that the macroscopic cracks in the brazing layer of active laser brazing diamond under ultrasonic action are suppressed,the brazing filler metal has better wetting and spreading properties to the diamond,and the thickness of the diamond-brazing filler interface transition layer increases.Compared with pure active laser brazing diamond,the diamond surface of ultrasonic-assisted active laser brazing also generates Cr7C3 on the basis of Cr3C2.(3)The test specimens prepared by the ultrasonic-assisted active laser brazing diamond technology were tested for the holding strength.The test results show that the damage form of the single-particle diamond specimens welded by ultrasonic-assisted active laser brazing is diamond fracture,while the damage form of some single-particle diamond specimens by pure laser brazing and active laser brazing is that the diamond is separated from the bond layer.Fall off.From the results of the shear force test,the bonding agent of the ultrasonic-assisted active laser brazing specimen has a higher holding strength on diamond than the pure laser brazing and active laser brazing specimens.