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헬륨가스분사법으로 제조된 Al86Ni6Ce4Mg4 비정질합금 분말과 성형재의 특성
배차헌,김성규,이병우,박흥일,정해용 ( Cha Hurn Bae,Sung Gyoo Kim,Byung Woo Lee,Heung Il Park,Hae Yong Jeong ) 한국주조공학회 1997 한국주조공학회지 Vol.17 No.2
N/A ]Properties of Al_(86)Ni_6Ce₄Mg₄, alloy powder produced by helium gas atomization process were investigated by using DSC, XRD, SEM and TEM. The powders below 32㎛ in diameter were identified as an amorphous phase mixed with a α-Al phase. Al_(86)Ni_6Ce₄Mg₄, bulk alloy was manufactured by hot extruding the alloy powders at various temperatures, and the estimation of its mechanical properties was carried out subsequently. As a result, the bulk alloy extruded at the temperature below 450℃ exhibited the microstructure in which the near-spherical shape of some powders below 20㎛ were nearly unchanged and fine voids between matrix and powders were formed during extrusion process. On the other hand, the tensile strength and elongation at room temperature for Al_(86)Ni_6Ce₄Mg₄, bulk alloy extruded at 450℃ were 750㎫ and 7.5%, respectively.
원심분사주조법에 의한 Cu-X(=Al2O3 , W)p 복합재료의 미세조직 및 복합화
배차헌,정해용 ( Cha Hurn Bae,Gae Yong Jeong ) 한국주조공학회 1997 한국주조공학회지 Vol.17 No.5
N/A Particle reinforced metal matrix composites(MMCs) via a centrifugal spray-cast deposition(CSD) process were fabricated by injecting second phase particles(Al₂O₃<40 )㎛, W<17.3 ㎛) into copper melt on the atomizing disc. Compositing modes were investigated by combining microstructures and mathematical modeling between Cu droplets and the reinforced particles injected. The Cu/W_P powders were shown that the W particles penetrate and get embedded in the Cu droplets. It is considered that the W particles composite preferentially in Cu melt on the atomizing disc. On the other hand, the Al₂O, particles did not penetrate into the Cu droplets on the atomizing disc but get attached in surface of Cu droplets during the flight. It is considered that the compositing may be attained in the flight distance which the relative velocity between Cu droplet and Al₂O, particle is maximum. The microstructure of the Cu/W_P and the Cu/(Al₂O,)_P composite preform was strongly influenced by compositing modes of droplets, and after subsequent deposition it was comprised as it is called the dispersed type and the cell type of microstructure,respectively. (Received July 24, 1997)
분사주조공정에 의하여 제조된 Al-Pb 과편정합금의 조직특성
배차헌,정해용,박흥일,김창업,이성렬 ( Cha Hurn Bae,Hae Young Jeong,Heung Il Park,Chang Up Kim,Sung Ryeol Lee ) 한국주조공학회 1992 한국주조공학회지 Vol.12 No.4
N/A In Al-Pb monotectic alloys Pb particles are difficult to uniformly distribute over the Al matrix because of the gravity segregation of pb element. Therefore the effects of centrifugally spray casting process on microstructures and distributions of Pb particle were investigated. As the preform thickened the sine of Pb particle became larger, the amount of porosity became lower and microstructures showed the change from spray-deposition microstructures in the lower part of the preform to spray-casting microstructures in the upper part of it. The size of Pb particles, amount of porosity and splat layer boundaries in hot forged preform showed still less than of as-deposited preform
박흥일,배차헌 ( Heung Il Park,Cha Hurn Bae,Siegfried Engler ) 한국주조공학회 1991 한국주조공학회지 Vol.11 No.2
N/A The purpose of this paper is to describe the solidification characteristics and the formation mechanism of in-situ composite structure with multilayer in the hypereutectic gray cast iron preform produced by centrifugal atomized spray casting process. The experimental work has been carried out in dry air atmosphere in the spray chamber. With increasing the thickness of preform, the solidification structure changes from a typical spray deposition structure with the splat boundaries to a typical spray casting structure without the splat boundaries. The effectiveness and the density of graphite nucleation, and the kinetics of growth of graphite should be higher on the interface of splats than the inner portion of splat. Consequently, graphite nucleates and grows preferentially on the interface of splats, and these splats are self-bonded tightly by the growth of graphite. The solidification mode of each splat showed the latest solidified zone in the center of splat, and these splats were consolidated with the unit component of in-situ composite structure which consists of the layer of graphite colonies, the layer of ferritic and pearlitic matrix, and the layer of segregated phase such as phosphides.
분사주조에 의한 입자강화 금속기지 복합재료의 제조시 액적의 열적거동과 미세조직에 대한 고찰
김명호,배차헌,정해용,박흥일 ( Myung Ho Kim,Cha Hurn Bae,Hae Young Jeong,Heung Il Park ) 한국주조공학회 1992 한국주조공학회지 Vol.12 No.4
N/A Particle-reinforced metal matrix composites via the Osprey spray casting process were fabricated by injecting second phase particles of Al₂O₃(<40㎛) and W(6㎛) into the spray of Cu droplets, and the thermal behaviors of the composite droplets during flight were considered theoretically on the basis of mixing modes between the Cu droplets and the reinforced particulates injected. It was found that the W-injected spray is comprised of particle-embedded droplets, and the Al₂O₃-injected spray comprises particle-attached droplets. From the predicted results of the thermal behaviors of the composite droplets and preforms produced, it is concluded that the thermal behaviors of the composite droplets during flight, and during the subsequent deposition are strongly influenced by its mixing modes between the reinforced particulates and Cu droplets during flight.
급냉응고된 Al-Li-X(=Ti , Zr) 합금의 석출거동에 관한 연구
정해용,배차헌,김인배,박세윤 ( Hae Yong Jeong,Cha Hurn Bae,In Bae Kim,Se Yun Park ) 한국주조공학회 1991 한국주조공학회지 Vol.11 No.2
N/A The Precipitation behavior of Al-Li-X(=Ti, Zr) alloys produced by a rapid solidification process and heat treated in the temperature range of 160℃ to 240℃ was investigated. The solid solubilty If Li atoms was shown to extend to 4.95w/o. The discontinuous precipitation reaction resulted from the preferential growth of δ´ phase. Also, the driving force of the growth was depend on the fluctuations of solute concentration. The coarsening rate of δ´phase followed a (time)^(⅓) dependency obeys the MLSW theory. The addition of Ti or Zr had a little effects on the formation amount better than the growth rate of δ´phase.
급속 응고한 Al-Pb 편정 합금의 조직과 성질 - 1. 급속 응고 조직 특성 -
김명호,배차헌,이호인 ( Myung Ho Kim,Cha Hurn Bae,Ho In Lee ) 한국주조공학회 1989 한국주조공학회지 Vol.9 No.1
N/A Microstructural characteristics of Al-3.63wt.% Pb hyper-monotectic alloy rapidly-solidified by melt spinning were examined. Possibility of forming a planar liquid-solid interface during rapid solidification of this alloy was also considered with a morphological stability theory, and a mechanism of forming banded structure observed at the bottom parts of melt-spinned specimens was considered as well. Application of the absolute stability criterion predicts the liquid-solid interface of the primary aluminium phase to be able to maintain a planar interface during the early stage of rapid solidification. Formation of banded structure was supposed to be resulted from the release of latent heat during solidification, which affect the stability of a planar liquid-solid interface.