• 제목/요약/키워드: heavy alloy

검색결과 166건 처리시간 0.017초

The Effects of the Distribution Aspect of Precipitate on the Corrosion Behavior of As-Cast Magnesium Alloys

  • 이충도
    • 소성∙가공
    • /
    • 제8권3호
    • /
    • pp.295-295
    • /
    • 1999
  • In the present study, the corrosion behavior of AZ91D as-cast alloy was investigated form the viewpoint of the distribution aspect of precipitate ($Mg_{17}Al_{12}$) and the variation of Al concentration in the Mg-rich matrix. The dendrite arm spacing (DAS) of an as-cast specimen was measured as a function of degree which describes the distribution aspect of the precipitate, and the salt spray test was conducted for various grain-sired specimens fur 20 days. The dendrite arm spacing increased as the grain size increased to about 150㎛, but a constant value is indicated when the grain size exceeds that range. Although the relationship between the corrosion rate and grain size is of a nonlinear type, the linear trend between the corrosion rate and the dendrite arm spacing is maintained for the overall range of dendrite arm spacing. Since the precipitate in the as-cast alloy is discontinuously distributed, this linear relationship means that the variation of Al-solute concentration in the Mg-rich matrix has a more potent effect than the protective action of the precipitate on the corrosion behavior of an as-cast alloy.

금속 염 첨가 방법을 이용하여 사출성형된 텅스텐 중합금의 소결거동 (Sintering Behavior of the Injection Molded W-Ni-Fe Heavy Alloy by Addition of Metallic Stat)

  • 김대건;류성수;김은표;이정근;김영도;문인형
    • 한국분말재료학회지
    • /
    • 제6권4호
    • /
    • pp.294-300
    • /
    • 1999
  • This study was carried out to investigate the possibility whether Metal Injection Molding (MIM) process could be applied to 95wt.%W-3.5wt.%Ni-1.5wt.%Fe heavy alloy in order to obtain an intricate shape. Methylcellulose was used in the injection molding for binder. $FeCl_2-4H_2O$ was added in solvent substituting Fe powder and $FeCl_2$ was doped on W-Ni premixed powder. When $FeCl_2-4H_2O$ was added in solvent, the binder separation occurred for injection molding so that the matrix content was changed. Such problem was solved when $FeCl_2$ was doped. In this study. the debinding process did not affect residual carbon content. The sintered microsouctures as addition methods of Fe element and the sintering temperature from $1420^{\circ}C$ to $1470^{\circ}C$, which are around the temperature of liquid phase formation, were observed.

  • PDF

동합금 조성에 따른 북방전복 (Haliotis discus hannai)의 생존, 호흡 및 중금속 축적률 (The survival rate, respiration and heavy metal accumulation of abalone (Haliotis discus hannai) rearing in the different copper alloy composition)

  • 신윤경;전제천;명정인;양성진
    • 한국패류학회지
    • /
    • 제30권4호
    • /
    • pp.353-361
    • /
    • 2014
  • 동합금이 사육 생물에게 미치는 생리적 영향을 조사하기 위해 화학적 조성이 다른 5종류의 금속판을 넣은 수조에서 사육한 북방전복을 대상으로 성패와 치패의 생존율, 호흡 및 배설률 그리고 기관별 중금속 축적률을 조사하였다. 생존율은 치패와 성패가 각각 27-60%와 63-83%로 성패가 더 높게 나타났다. 합금 조성에 따른 생존율의 뚜렷한 차이는 나타나지 않으나 중금속 축적률 그리고 영양적인 스트레스 등을 고려하면 동합금망은 전복 양성을 위한 가두리로서는 적합하지 못할 것으로 사료된다.