• 제목/요약/키워드: Powder consolidation

검색결과 164건 처리시간 0.023초

고압비틀림 공정을 통한 급속응고 MgZn4.3Y0.7 합금 분말의 치밀화 및 기계적 거동 (Consolidation and Mechanical Behavior of Gas Atomized MgZn4.3Y0.7 Alloy Powders using High Pressure Torsion)

  • 윤은유;채홍준;김택수;이종수;김형섭
    • 한국분말재료학회지
    • /
    • 제17권3호
    • /
    • pp.190-196
    • /
    • 2010
  • In this paper, rapid solidified Mg-4.3Zn-0.7Y (at.%) alloy powders were prepared using an inert gas atomizer, followed by a severe plastic deformation technique of high pressure torsion (HPT) for consolidation of the powders. The gas atomized powders were almost spherical in shape, and grain size was as fine as less than $5\;{\mu}m$ due to rapid solidification. Plastic deformation responses during HPT were simulated using the finite element method, which shows in good agreement with the analytical solutions of a strain expression in torsion. Varying the HPT processing temperature from ambient to 473 K, the behavior of powder consolidation, matrix microstructural evolution and mechanical properties of the compacts was investigated. The gas atomized powders were deformed plastically as well as fully densified, resulting in effective grain size refinements and enhanced microhardness values.

자기펄스 압축성형법에 의한 다이아몬드 공구용 세그먼트 분말 성형 (Consolidation of Segment Powder for Diamond Tool by Magnetic Pulsed Compaction)

  • 윤종수;이정구;이민구;이창규;박문석;홍순직
    • 한국분말재료학회지
    • /
    • 제15권5호
    • /
    • pp.378-385
    • /
    • 2008
  • This article presents the successful consolidation of the mixed Co and Diamond powders for a drilling segment by the combined application of magnetic pulsed compaction (MPC) and subsequent sintering, and their properties were analyzed. Homogeneous hardness (Hv 220) and density (97%) of sintered bulks fabricated by MPC were obtained by the new technique, where higher pressure has been employed for short period of time than that of general process. A fine microstructure and homogeneous hardness in the consolidated bulk were observed without cracks. Relatively higher drilling speed of 9.61 cm/min and life time of 6.55 m were found to the MPCed specimens, whereas the value of the specimens fabricated by general process was 11.71 cm/min and 7.96 m, respectively. A substantial improvement of mechanical properties of segment was achieved through this study.

Magnetic Properties of Amorphous FeCrSiBC Alloy Powder Cores Using Phosphate-coated Powders

  • Jang, Dae-Ho;Kim, Kwang-Youn;Noh, Tae-Hwan
    • Journal of Magnetics
    • /
    • 제11권3호
    • /
    • pp.126-129
    • /
    • 2006
  • The phosphate coating on the $(Fe_{0.97}Cr_{0.03})_{76}(Si_{0.5}B_{0.5})_{22}C_2$ amorphous powders with an average size of 10 ${\mu}m$ in diameter has been carried out in aqueous 1.0-2.0 wt% $H_3PO_4$ solutions, and the consolidation behavior and magnetic properties of their compressed powder cores has been investigated. The phosphate coating could provide efficient electrical insulation between amorphous powders and improved consolidation ability at room temperature. Especially when the powders were treated in more concentrated phosphoric acid solution, enhanced phosphate covering and higher frequency/dc-bias stability were achieved. The powder cores phosphate-coated in 2.0 wt% $H_3PO_4$ solution exhibited constant permeability of 21 up to 10 MHz, 110 of the quality factor at 0.9 MHz, 610 mW/cm3 core loss at 100 kHz/0.1 T and 89 of percent permeability at 100 kHz.