http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
조경목,박익민,이성학,전형준 대한금속재료학회(대한금속학회) 1993 대한금속·재료학회지 Vol.31 No.5
Simulation study employing metal thermal cycle simulator (MTCS) has been performed to investigate a correlation between the microstructure and fracture properties of the heat affected zone (HAZ) in welded HY-100 steel. Charpy impact energy dropped from 210 J to about 125 J after the first thermal cycle in the range of peak temperature (T_P¹) of 800℃∼1100℃, and decreased rapidly above 1100℃, down to 60 J for T_P¹=1350℃. Decreased Charpy impact energy of T_P¹=1350℃ appears to be due to the change of microstructure from tempered martensite to mixture of fresh martensite and fresh lower bainite. Impact transition temperature increased by the amount of 70℃ after thermal cycle simulation of T_P¹=1350℃, namely -50℃ in HAZ and -120℃ in HY-100 steel. Evaluation of Charpy impact result, after the second thermal cycle in the range of peak temperature (T_P²) of 700℃∼1300℃, revealed that the fracture properties of HAZ are not affected significantly by second thermal cycle in HY-100 steel.
조경목,오광중,박대원,홍성수,양진섭,류봉기 한국공업화학회 1997 응용화학 Vol.1 No.2
Catalytic removal of soot particulate in the presence of excess oxygen was investigated over perovskite-type oxides by using temperature programmed reaction(TPR) in which carbon particulate/catalyst mixture was heated in the reaction gas containing nitric oxide and oxygen. LaCoO₃ catalyst was modified to enhance the activity by substitution of metal ion into A and B sites. The reaction conditions was also examined.
자동차 차체용 고강도 IF 강에서 미세조직과 기계적 성질에 미치는 Mn 의 영향
조경목,정우창 대한금속재료학회(대한금속학회) 1999 대한금속·재료학회지 Vol.37 No.6
The purpose of this study was to develope IF(interstitial free) steels for the application to automotive body panels. IF steels containing less than 20 wt ppm of C and N, and 1.2 to 2.8 wt% of Mn were prepared to investigate the effect of Mn on the microstructure and mechanical properties. Microstructure observation of IF steels annealed at austenitic region revealed network type polygonal ferrite due to Mn gradient for the steels containing 1.23% Mn(A) and 1.94% Mn(B), and granular bainitic ferrite with high dislocation density for the steel containing 2.76%Mn(C). Tensile strength of A. B and C after annealing (800-920℃) was measured as about 400, 450 and 500 ㎫, respectively Tensile strength decreased slightly for A and B, butincreased for C with increasing annealing temperature. Granular bainitic ferrite of C might induce the strengthening effect at a high annealing temperature. (Fe. Ti) P precipitates formed when IF steels were annealed at ferritic region, which lead to the shortage of effective Ti content to remove solute carbon. The major texture of IF steels was found to be (554)[225 ̄] that is favorable to improve the formability. However, intensity of (554)[225 ̄] was decreased with increasing Mn content.
조경목,이후철,현태욱 대한금속재료학회(대한금속학회) 1985 대한금속·재료학회지 Vol.23 No.1
A study on the fracture toughness of WC-Co using alloys is made single-edge notched beam specimens pre-cracked by electron-discharge machining. The microstructural parameters are determined on the electron micrographs by linear analysis. The relations between K_(IC) and the microstructural parameters show that K_(IC) tends to increase with increased binder volume fraction and cobalt mean free path and tends to decrease with increases in WC contiguity, but cannot be related only to one microstructural parameter. A structure model is sugested to estimate the fracture path in WC-Co alloys and the critical strain energy release rate is evaluated from this fracture model.
란타노이드계 페롭스카이트형 촉매에서 입자상물질의 산화반응
조경목,오광중,박대원,홍성수,양진섭,류봉기 한국공업화학회 1998 응용화학 Vol.2 No.1
We have studied the catalytic combustion of soot particulate over perovskitetype oxides prepared by malic acid method. The catalysts were modified to enhance the activity by substitution of metal into A or B site of perovskite oxide. In addition, the reaction conditions, such as temperature, O₂ concentration, space velocity have been studied. The effect of SO₂ pretreatment and water introduced into reactants were also examined. In the LaCoO₃ catalyst, the partial substitution of alkali metals into A site enhanced the catalytic activity in the combustion of soot particulate and the activity was shown in the order: Cs$gt;K$gt;Na; In the Lao_0.6Cs_(0.4)CoO₃ catalyst, the substitution of Fe or Mn showed no effect on the ignition temperature. The ignition temperature decreased with increasing O₂ concentration and contact time. The introduction of water into reactants feed decreased the ignition temperature and the pretreatment of SO₂ showed no effect on the catalytic activity.
조경목,박익민,최일동,송대현,최홍석 대한금속재료학회(대한금속학회) 2000 대한금속·재료학회지 Vol.38 No.6
In the present study, Al-SiC_p FGMs containing 10 layers with different volume fraction of Al and SiC_p, and different geometry in thickness (3 ㎜, 5 ㎜ and 7 ㎜) were fabricated by employing the pressureless infiltration technique. Optimum condition was established to obtain the enough strength of preforms by controlling the forming pressure and binder added. Al-10%Mg was properly infiltrated into the preforms at 920℃ with N₂ atmosphere within a tube furnace. Analysis of microstructure and mechanical properties revealed that Al-SiC_p FGMs were fabricated successfully. Curvature of Al-SiC_p FGMs plates was measured to predict the internal stress distribution via a theoretical model for the analysis of thermo-mechanical deformation.