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http://dx.doi.org/10.9725/kstle.2015.31.4.157

Changes in Mechanical Properties of WC-Co by Ultrasonic Nanocrystal Surface Modification Technique  

Lee, Seung-Chul (Graduate School, Dept. of Mechanical Engineering, Sun Moon University)
Kim, Jun-Hyong (Graduate School, Dept. of Mechanical Engineering, Sun Moon University)
Kim, Hak-Doo (Graduate School, Dept. of Mechanical Engineering, Sun Moon University)
Choi, Gab-Su (Graduate School, Dept. of Mechanical Engineering, Sun Moon University)
Amanov, Auezhan (Dept. of Mechanical Engineering, Sun Moon University)
Pyun, Young-Sik (Dept. of Mechanical Engineering, Sun Moon University)
Publication Information
Tribology and Lubricants / v.31, no.4, 2015 , pp. 157-162 More about this Journal
Abstract
In this study, an ultrasonic nanocrystalline surface modification (UNSM) technique is applied to tungsten carbide-cobalt (WC-Co) to extend the service life of carbide parts used in press mold. The UNSM technique modifies the structure, reduces the surface roughness, increases the surface hardness, induces the compressive residual stress, and increases the wear resistance of materials by introducing severe plastic deformation. The surface roughness, hardness, and compressive residual stress of WC after UNSM treatment improve by about 42, 10, and 71%, respectively. A wear test under dry conditions is used to assess the effectiveness of the UNSM technique on the friction and wear behavior of WC. The UNSM technique is found to reduce the WC friction coefficient by approximately 21% and enhance the wear resistance by approximately 85%. The improved friction and wear behavior of WC may be mainly attributed to the increased hardness and compressive residual stress. Moreover, the WC specimen is treated by UNSM technique using three different WC, silicon nitride (Si3N4) and stainless steel (STS304) balls. The surface treated by WC balls shows the highest hardness when compared with treatment by stainless steel and silicon nitride balls. According to the obtained results, the UNSM technique is believed to increase the durability of the carbide component by improving the friction and wear behavior.
Keywords
dimple; press die; tungsten carbide-cobalt; surface hardness; ultrasonic nanocrystal surface modification;
Citations & Related Records
Times Cited By KSCI : 2  (Citation Analysis)
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