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Changes in Mechanical Properties of WC-Co by Ultrasonic Nanocrystal Surface Modification Technique
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  • Journal title : Tribology and Lubricants
  • Volume 31, Issue 4,  2015, pp.157-162
  • Publisher : The Korean Society of Tribologists and Lubrication Engineers
  • DOI : 10.9725/kstle.2015.31.4.157
 Title & Authors
Changes in Mechanical Properties of WC-Co by Ultrasonic Nanocrystal Surface Modification Technique
Lee, Seung-Chul; Kim, Jun-Hyong; Kim, Hak-Doo; Choi, Gab-Su; Amanov, Auezhan; Pyun, Young-Sik;
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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.
dimple;press die;tungsten carbide-cobalt;surface hardness;ultrasonic nanocrystal surface modification;
 Cited by
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Amanov, A., Cho, I. S., Pyoun, Y. S., Lee, C. S., Park, I. G., “Micro-dimpled Surface by Ultrasonic Nanocrystal Surface Modification and its Tribological Effects”, Wear, Vols. 286-287, pp. 136-144, 2012. crossref(new window)

Pyun, Y. S., Suh, C. M., Yamaguchi, T., Im, J. S., Kim, J. H., Amanov, A., Park, J. H., “Fatigue Characteristics of SAE52100 Steel via Ultrasonic Nanocrystal Surface Modification Technology”, Journal of Nanoscience and Nanotechnology, Vol. 12, pp. 6089-6095, 2012. crossref(new window)