• 제목/요약/키워드: Semi-Solid Alloy

검색결과 110건 처리시간 0.023초

반용융 알루미늄재료의 단조공정조건이 기계적 성질에 미치는 영향 (The effect of forging process conditions of semi-solid aluminum material on mechanical properties)

  • 강충길;강동우
    • 대한기계학회논문집A
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    • 제21권9호
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    • pp.1400-1413
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    • 1997
  • Semi-solid forging(SSF) process of A356 aluminium alloy has been studied to assess the effect of process variables on the component integrity. Semi-solid material(SSM) was fabricated by mechanical and electro-magnetic stirring process. The fabricated SSM by using mechanical stirring process has been carried out on cooling rate of 0.022.deg. C/sec 0.0094.deg. C/sec and stirring speed n=600, 1000 rpm, respectively. The fabricated SSM by using electro-magnetic stirring process is supplied by Pechiney. The holding time and temperature in the semi-solid state before forging also affects the globular microstructure of alloy. Therefore, the influence of these two parameters is discussed in terms of the microstructure of alloy. The SSF process has been conducted with three different die temperatures($T_{die}$=250.deg. C, 300.deg. C, 350.deg. C) and two kinds of gate types(straight gate and orifice gate). This paper is to investigate the influence of gate shapes of die on filling phenomena in SSF process more deeply. The mechanical properties of forged components were also investigated for variation of process conditions such as die temperature, gate shape and SSM.

경사냉각판을 이용한 Al-Zn-Mg-(Sc) 반응고 합금 제조의 최적화 및 재가열 특성 (Optimum Fabrication Conditions and Reheating Characteristic of Semi-Solid Al-Zn-Mg-(Sc) Alloy by Inclined Cooling Plate)

  • 김태훈;심성용;박형원;임수근
    • 한국주조공학회지
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    • 제29권5호
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    • pp.213-219
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    • 2009
  • Optimum conditions for production of semi-solid Al-Zn-Mg alloy billets was carried out by the Taguchi design method. And, Al-Zn-Mg alloy billets contained Sc (free, 0.1 and 0.3 mass %) were fabricated at optimum conditions. Evolution of microstructure in semi-solid state was investigated through various liquid fractions, holding times and holding temperatures. The Al-Zn-Mg alloy billets reheated at $615^{\circ}C$ during 30min are grain growth and it was fractured due to increasing liquid fraction before quenching. And, during reheating up to $600^{\circ}C$, grain growth of Al-Zn-Mg alloy billets contained Sc (0.1 and 0.3 mass %) was not occurred in comparison with those of Al-Zn-Mg alloy without Sc. It was thought that $Al_3Sc$ phases have a pinning effect in grain boundary and Sc content of 0.1 mass% is able to inhibit grain growth effectively through reheating process.

나선형 기계 교반 레오로지 소재의 이용한 Thixoforging 공정 (Thixoforging Process of Rheology Materials fabricated by Spiral Mechanical Stirring)

  • 한수훈;정일갑;배정운;강충길
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2007년도 춘계학술대회 논문집
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    • pp.131-134
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    • 2007
  • A semi-solid forming technology has a lot of advantages compared to the die casting, squeeze casting and hot/cold forging, so semi-solid forming has been studied actively. Semi-solid forming has two methods. One is thixoforming with reheating of prepared billet, the other is rheoforming with cooled melt until semi-solid state. Thixoforging technology can produce non-dendritic alloys for semi-solid forming complex shaped parts in metal alloys. In this study, the thixoforging was experimented with made rheology materials by the spiral stirrer equipment. Rheology materials for forging were made by A356 casting aluminum alloy and A6061 wrought aluminum alloy. After experiment, forged samples were measured microstructure and were heat treated for high mechanical properties.

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AM80-xSn 마그네슘 합금의 반응고 주조 및 압출에 따른 미세조직 및 기계적 특성 (Microstructures and Mechanical Properties of AM80-xSn Magnesium Alloys with Semi-Solid casting and Hot Extrusion Process)

  • 김대환;임인택;;임수근
    • 한국주조공학회지
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    • 제36권6호
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    • pp.215-221
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    • 2016
  • In a recent study, the microstructures and mechanical properties of AM80-xSn magnesium alloys with semi solid casting and hot extrusion process were investigated. With increasing Sn content, the amount of ${\beta}$(Mg2Sn) phase increased, while the ${\alpha}-Mg$ dendritic size decreased. The hardness was increased by the Mg2Sn as the Sn content increased. With increasing Sn content, permanent mold cast and semi solid cast AM80 Mg alloy showed less reduction of hardness and also of extruded AM80 Mg alloy after annealing. In the case of the mechanical properties, the extruded semi solid casting AM80 Mg alloy showed higher tensile strength and yield strength with increasing Sn content compared to the extruded permanent mold cast AM80 Mg alloy at room temperature.

반응고 Al-Zn-Mg 합금의 고온 압출 시 특성 평가 (Characteristics on the Hot Extrusion of Semi-Solid Al-Zn-Mg Alloy)

  • 조국래;김정한;염종택;심성용;임수근;박노광
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2007년도 춘계학술대회 논문집
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    • pp.405-408
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    • 2007
  • Semi-solid Al-Zn-Mg alloys were produced using a cooling plate method in order to investigate the extrudability. Al melt was poured on cooling plate which was adjusted at $60^{\circ}$ with respect to the horizontal plane, and the melt was cooled by water circulation underneath. Obtained Semi-solid feedstock has globular microstructure but also contains considerable amount of gas pore. Due to the pore, tensile elongation of the semi-solid feedstock was very low and it doesn't show yield point phenomenon. Isothermal hot extrusion was carried out using at $400^{\circ}C$ with a ram speed of 1mm/sec and an extrusion ratio of 25:1. The extruded bar show noticeably improved tensile ductility and strength because pore volume fraction decreased from 5% to 0.8% after extrusion. Mechanical properties of the semi-solid extruded bar were compared with that of commercial casting alloy..

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반용융 Al-Zn-Mg합금의 고온 압출 시 특성 평가 (Characteristics on the Hot Extrusion of Semi-Solid Al-Zn-Mg Alloy)

  • 조국래;염종택;심성용;임수근;박노광;김정한
    • 소성∙가공
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    • 제16권5호통권95호
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    • pp.391-395
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    • 2007
  • Semi-solid Al-Zn-Mg alloys were produced by using a cooling plate method in order to investigate the extrudability. Al melt was poured on cooling plate which was adjusted at $60^{\circ}$ with respect to the horizontal plane, and the melt was cooled by water circulation underneath. Obtained Semi-solid feedstock has globular microstructure but also contains considerable amount of gas pore. Due to the pore, tensile elongation of the semi-solid feedstock was very low and it doesn't show yield point phenomenon. Isothermal hot extrusion was carried out using at $400^{\circ}C$ with a ram speed of 1mm/sec and an extrusion ratio of 25:1. The extruded bar show noticeably improved tensile ductility and strength because pore volume fraction decreased from 5% to 0.8% after extrusion. Mechanical properties of the semi-solid extruded bar were compared with that of commercial casting alloy.

나노인덴터와 원자력간 현미경을 이용한 결정립 제어 레오로지 소재의 변형거동에 관한 연구 (A Study on Deformation Behavior of the Grain-Size Controlled Rheology Material by Using Nanoindenter and AFM)

  • 윤성원;김정원;강충길
    • 소성∙가공
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    • 제13권4호
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    • pp.374-381
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    • 2004
  • In this study, the deformation behavior of semi-solid Al-Si alloy was investigated by nanoindenter as a part of the research on the surface crack behavior in thixoformed automobile component. The microstructure of semi-solid Al-Si alloy consists of primary and eutectic regions. In eutectic regions the crack initiation begins with initial fracture of the eutectic silicon particles and inside other intermetallic phases. Nano-deformation characteristics in the eutectic and primary phase of semi-solid aluminium alloy were investigated through the nano-indentation experiments and the AFM observation. In addition, mechanical properties of each region were investigated and compared with each other.

반고상 가공과 공정 Al-Si 합금에서 $\alpha$-halo의 형성 ($\alpha$-halo formation in semi-solid state processed hypereutectic Al-Si alloy)

  • 김인준;김도향
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 1997년도 고액공존금속의 성형기술 심포지엄
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    • pp.183-195
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    • 1997
  • The micorstructural characteristics, particularly $\alpha$-halo formation, in semi-solid state processed hypereutectic Al-Si alloy was investigated. The microstructural changes during reheating of wedge type mold cast ingot, hot-rolled sheet, and Si particulate reinforced Al composite was compared with those occurred during stirring of semi-solid state hypereutectic alloy. In the case of semi-solid state reheating of wedge type ingot and hot-rolled sheet, fine particles of Si as well as $\alpha$-halo formed after heat treatment. Although there seemed to be no coarsening with variations of holding time, the region of $\alpha$-halo decreased due to homogenization. Nucleation and recrystallization was accelerated with the addition of alloying elements during hot rolling resulting in primary Si particle size decrease and $\alpha$-halo formation. In the case of extruded specimens, very little morphological change of reinforcing Si particles was observed. Almost no $\alpha$-halo formed during reheating because of the oxide film formed on the reinforcing Si particles which acted as a diffusion barrier between the matrix and the primary Si particles.

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Computer Simulation for Die Filling Behavior of Semi-Solid Slurry of Mg Alloy

  • Lee, Dock-Young;Moon, Jung-Hwa;Seok, Hyun-Kwang;Kim, Sung-Bin;Kim, Ki-Bae
    • 한국주조공학회지
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    • 제27권1호
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    • pp.31-35
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    • 2007
  • 본 연구에서는 Mg합금의 반응고성형 공정기술을 개발하기 위하여 여러 가지 전단속도와 냉각속도에 따른 Mg합금의 점도와 딕소트러픽 거동을 분석하였으며, 이를 전산모사연구와 비교 검토하였다. 전산모사연구에서는 미세조직과 공정변수를 고려한 반응고 슬러리의 유변학적 거동을 분석하였다. 반응고 온도영역에서의 Mg합금(AZ91D) 슬러리의 점도는 고상율에 따라 지수함수적으로 증가하였으며, 전단속도가 증가하면 감소하는 경향을 나타났다. Mg합금 슬러리의 유변학적 거동을 정확하게 분석하기 위하여 Carreau 모델을 사용하여 ANYCAST 프로그램에서 고압다이캐스팅용 금형으로의 Mg합금 반응고 슬러리의 충진거동을 모사하였다. 전산모사된 결과는 동일한 조건에서의 실제 실험결과와 잘 일치하였다.

냉각판으로 제조한 반응고 AM100A 마그네슘 합금의 미세조직 및 열간 압출성 (The Microstructures and Hot Extrudability of Semi-solid AM100A Magnesium Alloy Fabricated by Cooling Plate)

  • 김대환;성영록;심성용;이상용;김광삼;임수근
    • 한국주조공학회지
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    • 제29권3호
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    • pp.144-149
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    • 2009
  • In this study, we investigated optimum condition of cooling plate method to obtain semi-solid AM100A Mg alloy with fine and globular morphology. AM100A Mg alloy were hot extruded at $380^{\circ}C$ extrusion temperature under extrusion ratio of 25 : 1 and ram speed of 2.4 mm/sec. Vickers hardness test, optical microscopy, scanning electron microscopy, and image analyzer were performed to identify the optimum conditions of cooling plate method. Optimum conditions of cooling plate method to fabricate semi-solid AM100A Mg alloy with fine and globular microstructures were achieved at a pouring temperature of $602^{\circ}C$ and the angle of cooling plate of 60 degree.