• Advances in materials Research
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• 제3권1호
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• pp.283-295
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• 2014

In this paper, the microstructure, hardness, tensile deformation and fracture behavior of high strength alloy steel X2M is presented anddiscussed. The influence of both composition and processing on microstructure of the as-provided material and resultant influence of microstructure, as a function of orientation, on hardness, tensile properties and final fracture behavior is highlighted. The macroscopic mode and intrinsic microscopic features that result from fracture of the steel specimens machined from the two orientations, longitudinal and transverse is discussed. The intrinsic microscopic mechanisms governing quasi-static deformation and final fracture behavior of this high strength steel are outlined in light of the effects oftest specimen orientation, intrinsic microstructural effects and nature of loading.

• 한국기계가공학회지
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• 제11권6호
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• pp.139-144
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• 2012

In the automobile industry, the various efforts to lower their industrial cost and enhance fuel efficiency have been made through process improvement or weight saving of automobile parts. Gear is one of significant parts of transmission, which is made by cast iron or alloy steel. It is expensive due to complex processing, inferior materials and large machining allowance. In this study, alternative gear cars oil which is based on fluid applications materials is produced by reducing surface induction hardening and carburizing hardened in production. And then, wear characteristic and mechanical properties such as hardness of the sintered alloy which is used as a substitute for small machining allowance is investigated.

• 한국재료학회지
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• 제18권5호
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• pp.259-265
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• 2008

The corrosion and degradation factors of a current collector in a molten carbonate fuel cell (MCFC) were investigated to determine the optimized coating thickness of nickel on STS316L. The results show that the surface morphology and electrical properties depended on the nickel coating thickness. The surface morphology gradually changed from a flat to a porous structure along as the nickel coating thickness decreased, and the electrical resistance of the nickel-coated STS316L increased as the nickel coating thickness decreased. This can be attributed to the diffusion of elements of Fe and Cr from the substrate through the nickel grain boundaries. Additionally, carburization in the metal grains or grain boundaries in an anodic environment was found to influence the electrical properties due to matrix distortion. The resistance of Cr-oxide layers formed in an anodic environment causes a drop in the potential, resulting in a decrease in the system efficiency.

• 자원리싸이클링
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• 제25권2호
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• pp.10-16
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• 2016

본 연구에서는 Inconel 713C 스크랩을 원료로 아르곤-산소 탈탄 공정을 이용하여 니켈계 초내열합금을 재활용 하였다. 아르곤-산소 탈탄 공정에서 아르곤은 1,000 sccm으로 지속적으로 주입되었고 산소는 100, 250, 500 sccm의 유량으로 10, 20, 30 분씩 주입되었다. 산소 주입 초기 단계에서는 산소 양이 증가하면서 Al, Cr, 및 Mo 함량은 증가하였고 탄소 함량은 감소하였다. 그리고 Al 함유량은 탄소의 반응이 끝난 후 Al, Cr 등의 원소와 산화가 일어났기 때문에 첨가원소와 탄소의 반응에 의해 감소하였다. 결과적으로, Al 함유량이 감소하였기 때문에 ${\gamma}^{\prime}$상이 줄어들었으며 이는 Al이 ${\gamma}^{\prime}$을 형성하는 주요 원소이기 때문이다. 또한, 탄소의 양이 줄어들면서 탄화물도 줄어들었으며 산소가 과잉 공급된 시료의 기계적인 물성(강도, 경도 등)은 감소하게 된다.