http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
오늘 본 자료
불변면 변형의 현상론적 이론에 기초한 B2→9R 마르텐사이트 변태의 결정학적 해석
이언식 대한금속재료학회(대한금속학회) 1997 대한금속·재료학회지 Vol.35 No.9
The phenomenological theory of martensitic transformation has been applied to crystallographic analysis of the B2 to 9R martensite transformation in Cu-Zn-Al shape memory alloys. The formulation procedure for solving the crystallographic relation between B2 and 9R phases is based on the basic concept of the invariant plane strain. Analytical crystallographic solutions have been derived to predict habit plane, direction and size of invariant plane strain, total shapede formation, orientation relationships between parent and martensite phases. Comparison between these derived solutions and experimental data has shown good agreement. It has been demonstrated that these analytical solutions are useful to understand various crystallographic features of the B2 to 9R martensite transformation.
이언식 한국분말야금학회 1997 한국분말재료학회지 (KPMI) Vol.4 No.1
High speed steels with commercial compositions of 10V, Rex20, Rex25, T15, and ASP30 were gas-atomized and then consolidated by hot isostatic pressing (HIPping). The microstructures of gas-atomized powder, as-HiPped billet, and heat-treated billet have been characterized using optical microscope, scanning electron microscope and X-ray diffractometer. In the gas-atomized powders, the solidification structures of 10V and Rex25 alloys show that primary MC carbides embedded within the fine equiaxed dendrites, whereas those of Rex20, T15 and ASP30 alloys exhibited eutectic MC and/or M$_2$C carbides in the interdendritic region. The trace and dendritic morphologies of gas-atomized powder have been retained in as-HiPped billets. The microstructures of as-HiPped billets have been observed to consist of ferrite, $M_6C$ and MC carbides in other alloys with the exception of 10V alloy, which consists of ferrite and MC carbides. The hardness of heat-treated billet makes a favorable comparison with that of as-HIPped billet. This seems mainly to be due to the strengthening by the precipitation of secondary carbides and the change of matrix phase from $\alpha$-ferrite to martensite.
분무성형 공정에서 분무액적의 열이력 해석 및 고상분율 예측
이언식 한국분말야금학회 1994 한국분말재료학회지 (KPMI) Vol.1 No.1
In order to predict droplet velocity and temperature profiles and fractional solidification with flight distance during spray forming, the Newtonian heat transfer formulation has been coupled with the classical heterogeneous nucleation and the specific solidification process. It has been demonstrated that the thermal profile of the droplet in flight is significantly affected by process parameters such as droplet size, initial gas velocity, undercooling. As the droplet size and/or the initial gas velocity increase, the onset and completion of solidification are shifted to greater flight distances and the solidification process also extends over a wider range of flight distances. The amounts of solid fractions formed during recoalescence, segregated solidification and eutectic solidification are insensitive to droplet size and initial gas velocity whereas those are strongly affected by the degree of undercooling. There are good linear relations between the undercooling and the corresponding solid fractions generated during recoalesced, segregated and eutectic stages.