http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Ti-Nb 복합 첨가강의 BH특성에 미치는 균열온도의 영향
허보영 ( Bo Young Hur ),엄용수 ( Yong Su Um ),김상열 ( Sang Youl Kim ),조상헌 ( Sang Hun Cho ),남태운 ( Tae Woon Nam ) 한국주조공학회 2004 한국주조공학회지 Vol.24 No.4
N/A Bake hardenable steel utilizes the phenomenon of strain aging to provide an increase in the yield strength of formed components. An increase of the carbon content will improve the bake hardening response: more solutes are available to pin mobile dislocations and to form the clusters more rapidly. But aging resistance decrease as increasing solute carbon. In order to under-stand the compatibility between bake hardenability and aging resistance. The optimum solute carbon control methods during manufacture should be determined. In this paper, the effect of continuous heat cycle conditions such as soaking temperature, rapid cooling start temperature, cooling rate on BH(Bake Hardenability), AI(Aging Index), YP-EI(Yield Point Elongation) and other mechanical properties have been investigated. and following results were obtained. In the case of soaking temperature, BH increases with higher soaking temperature because of NbC dissolution(830℃), Therefore the solute carbon and BH at 850℃ and 870℃ are higher than these at 810℃. But BH at 870℃ is a little lower than that at 850℃ owing to the ferrite grain size. The measurement of amount of dissolution C using IFT(Internal Friction Test) can explain the relation of solute carbon and BH.
급냉응고와 원소첨가에 의한 Mg-Zn 합금의 미세조직 제어
김연욱,허보영 ( Yeon Wook Kim,Bo Young Hur ) 한국주조공학회 1998 한국주조공학회지 Vol.18 No.3
N/A Interest in rapid solidification of magnesium alloys stems from the fact that conventional ingot metallurgy alloys exhibit poor strength, ductility, and corrosion resistance. Such properties can be improved by microstructural refinement via rapid solidification processing. In this study, Mg-Zn alloys have been produced as continuous strips by melt overflow technique. In order to evaluate the influence of additional elements on the grain refinement and mechanical properties, Th and Zr were added in rapidly solidified Mg-5wt%Zn alloy. Then the microstructual observations were undertaken with the objective of evaluating the grain refinement as function of the cooling rate and the additional elements. The tremendous increase in hardness of Mg-Zn base alloys was mainly due to the refinement of the grain structure by the effect of rapid solidification and alloying elements. The formation of intermetallic phases on the grain boundaries may have a positive effect on the corroion resistance. Therefore, despite competition from many other developments, the rapid solidification processing of magnesium alloys emerges as a valuable method to develop superior and commercially acceptable magnesium alloys. (Received May 14, 1998)
급냉응고에 의한 Mg-5wt%Zn 합금의 결정립 미세화
김연욱,이은종,허보영 ( Yeon Wook Kim,Eun Jong Lee,Bo Young Hur ) 한국주조공학회 1997 한국주조공학회지 Vol.17 No.3
N/A In spite of the fact that magnesium has low density and good machinability, its applications are restricted as a structural engineering material because of the poor strength, ductility, and corrosion resistance of the conventional ingot metallurgy alloys. Such properties can be improved by microstructural refinement via rapid solidification processing. In this study, Mg-5wt%Zn alloys have been produced as continuous strips by the melt overflow technique. In order to evaluate the influence of the cooling rate on the grain refinement and mechanical properties, seven different thickness strips were produced by means of controlling the speed of the cooling wheel. Then the microstructual observations were undertaken with the objective of evaluating the grain refinement as function of the cooling rate. The tremendous increase in hardness of Mg-Zn alloy was mainly due to the refinement of the grain structure by the effect of rapid solidification. The formation of intermetallic phases on the grain boundaries may have a positive effect on the corroion resistance. Therefore, despite competition from many other developments, the rapid solidification process emerges as a valuable method to develop superior and commercially acceptable magnesium alloys.
Ar 가스 분위기에서 제조한 Mg-Zn-(Mn) 합금의 미세조직
엄정필,임수근,허보영 ( Jeong Pil Eom,Su Guen Lim,Bo Young Hur ) 한국주조공학회 1996 한국주조공학회지 Vol.16 No.4
N/A The microstructure of Mg-1∼6wt%Zn, Mg-1.5wt%Mn and Mg-3,6wt%Zn-lwt%Mn alloys were investigated by means of optical microscopy, scanning electron microscopy and energy dispersive spectroscopy. The liquid Mg alloys were tasted into the metallic mold at room temperature, and cooling part was located at the bottom of mold. The microstructure of Mg-Zn cast alloys revealed that MgZn compounds were around the secondary dendrite arms. Scanning electron microscopy and energy dispersive spectroscopy showed that the composition of MgZn compound was Mg-77wt%Zn. The addition of Mn in Mg-Zn alloys refined the grain size in as tasted alloys. Manganese additions also increased the Vickers hardness.
Mg-Zn-(Mn)-Ca 합금의 미세조직 및 기계적 성질
엄정필,차동득,임수근,허보영 ( Jeong Pil Eom,Dong Deuk Cha,Su Guen Lim,Bo Young Hur ) 한국주조공학회 1997 한국주조공학회지 Vol.17 No.6
N/A The microstructure and tensile properties of Mg-Zn-Ca and Mg-Zn-Mn-Ca alloys have been investigated. The alloys were obtained by melting in a low carbon crucible coated with boron nitride under an Ar gas atmosphere to prevent oxidation and combustion. The Mg alloy melt was cast into the metallic mold at room temperature, and cooling part was located at the bottom of mold. The phase formed during solidification of the Mg-Zn-(Mn) alloys containing 0.5%Ca is Ca₂Mg_6Zn₃,. The yield strength and ultimate tensile strength of the alloys increased with increasing Zn content, but the ductility did not change with increasing Zn content. The addition of Mn improves the yield strength and ultimate tensile strength of the alloys, but the ductility did not change. Tensile fracture of the alloys revealed brittle failure, with cracking along the Ca₂Mg_6Zn₃, phase. The variation of stress with strain obeyed the relationship of the σ=Kε. (Received October 21, 1997)
Al-Zn-Mg-Cu 발포합금 제조 및 흡음특성에 관한 연구
정승룡 ( Seung Reung Jeong ),허보영 ( Bo Young Hur ) 한국주조공학회 2011 한국주조공학회지 Vol.31 No.3
Metallic foam has been known as a functional material which can be used for absorption properties of energy and sound. The unique characteristics of Al foam of mechanical, acoustic, thermal properties depend on density, cell size distribution and cell size, and these characteristics expected to apply industry field. Al-Zn-Mg-Cu alloy foams was fabricated by following process; firstly melting the Al alloy, thickening process of addition of Ca granule to increased of viscosity, foaming process of addition of titanium hydride powder to make the pores, holding in the furnace to form of cooling down to the room temperature. Metal foams with various porosity level were manufactured by change the foaming temperature. Compressive strength of the Al alloy foams was 2 times higher at 88% porosity and 1.2 times higher at 92% porosity than pure Al foams. It`s sound and vibration absorption coefficient were higher than pure Al foams and with increasing porosity.