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Vol.55, No.11, 783 ~ 790, 2017
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| Title |
| Fabrication and Mechanical Properties of WC Alloy Hard Materials by a Pulsed Current Activated Sintering Method |
| 이정한 Jeong-han Lee , 박현국 Hyun-kuk Park , 장준호 Jun-ho Jang , 홍성길 Sung-kil Hong , 오익현 Ik-hyun Oh |
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| Abstract |
| In this study, planetary ball milled WC-5 wt%Co powders were sintered using the pulsed current activated sintering (PCAS) process. With this process, fully densified hard materials were obtained in a shorter time than conventional processes such as a HP and HIP. The particle sizes of the planetary ball milled WC and Co were 0.114 μm and 0.154 μm, respectively. The PCAS process was performed at temperatures up to 1300 ℃ with 60 MPa and electric current for 13 min without any significant change in the grain size. The WC-5 wt% Co hard materials were fully densified with a relative density of up to 99.8%. The density of WC-5 wt% Co hard materials increased with increasing shrinkage ratio. In addition, the Co particles penetrated into the WC particles by dissolving and re-precipitation, and finally hard materials were completely densified. The average grain size of the WC-5 wt%Co was 0.25 μm, and the hardness and fracture toughness were 2,386 kg/mm2 and 6.0 MPa·m1/2, respectively. The mechanical properties of the WC-5 wt% Co hard materials were excellent because of grain refinement and densification.
(Received June 9, 2017; Accepted July 12, 2017) |
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| Key Words |
| pulsed current activated sintering process, rapid sintering, WC-.Co, planetary ball milling, mechanical property |
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