Al-1.0 % Mg2Si의 이원계합금의 G. P. Zone 형성과 시효석출에 미치는 Fe 첨가의 영향

조현기,윤병하,정인상 대한금속재료학회(대한금속학회) 1973 대한금속·재료학회지 Vol.11 No.1

Al-1.0% Mg₂Si 擬二元系合金에 微量(0.05∼0.16%)의 Fe를 첨가하여 G.P. zone형성과 각종 時效擧動을 硬度 및 電氣抵抗 測定에 의해서 檢討한 결과 다음과 같았다. (1) 低溫時效에서는 G.P. zone의 형성이 지연되었고 高溫時效에서는 G.P. zone의 형성 없이 析出反應만이 빠르게 일어났다. (2) G.P. zone의 臨界溫度는 208℃였고 Fe첨가에 의해 그 臨界溫度는 낮아져서 0.16% Fe 첨가시 160℃였다. (3) 時效初期의 硬度置는 Fe첨가에 의해 약간 증가되었다. 이상의 결과는 溶體化處理溫度에서도 용해되지 않은 一部의 Fe化合物이 有效 vacancy 농도와 有效 용질원자 농도를 감소시키고 析出物의 성장을 촉진시키기 때문이다. The effects of additional clement Fe in the range of 0.05-0.16% on G.P. zone formation and ageing phenomena in Al-1.0% Mg₂Si pseudo binary alloy were investigated by means of Vickers microhardness and electrical resistivity measurement. The results obtained were summarized as follows: (1) The G.P. zone formation was delayed in low temperature ageing and the rate of precipitation was increased without G.P. zone formation in high temperature ageing by the additional element Fe. (2) The critical temperature of G.P. zone was 208℃, and it was dropped down by the effect of additional element Fe as 160℃ at the 0.16% Fe content. (3) The hardness of specimens added element Fe were a little higher than that of matrix alloy in the initial ageing time. The above results can be explained by the facts that Fe compounds in the alloy undisolved even at solution treatment temperature decreases the concentration of effective vacancy and solute atom, and also accelerate the growth of precipitate in the alloy.

일방향 응고시킨 Al-Fe 2원 공정합금의 응고조직과 기계적성질에 미치는 Zr 첨가의영향

趙顯麒,林相元 慶北大學校 1989 論文集 Vol.47 No.-

Effects of Zr addition on structure and mechanical properties in unidirectionally solidifed Al-Fe eutectic alloy have been carried out by means of scanning electron micrography and the measurement of hardness and tensile strength. Especially, effects of Zr addition on ageing behaviours and precipitate distributions have been also conducted by the observation of transmission electron microscope. At first, by the addition of Zr, the eutectic fibre produced were very fine but, as the growth rate increase, the mechanical properties were somewhat deteriorated at room temperature by misalignment of fibre due to constitutional supersooling. On the other hand, Al_3Zr phases were precipitated in interface of matrix/fibre by the ageing at 365℃ for 50 hrs and these phase contributed to increase the mechanical properties remarkablely from RT to 500℃. This results deduced that the shear slip in interface was suppressed by Al_sZr precipitates which mitigated the difference of heat expansion coefficient between matrix and fibre.

규소강판의 자기적 성질에 미치는 열처리 온도와 그 항온 유지시간에 과한 연구

조현기,윤병하,김동의 慶北大學校 1972 論文集 Vol.16 No.-

The ironloss of 3.25wt% Si-steel has been investigated in the temperature range between 800℃ and 900℃ and holding time range 6 and 13 hours. Results of this experiment showed that the specimen treated for 10 hours at 850℃ has the lowest ironloss value, W￣10;1.7 watts/㎏. Also, the 1.1∼1.4wt% Si-steel which were treated for 6 hours at 850℃ have the lowest ironloss value, W￣10;2.46 watts/㎏.

Damping Mechanism in High Damping Alloy : Mn-Cu계 합금을 중심으로

최광재,조현기 국립경상대학교 공과대학 부설 첨단소재연구소 1996 尖端素材 Vol.6 No.-

Al-Mg-Si合金의 時效擧動에 미치는 加工熱處理의 影響

趙顯麒,李基大,朴定國 慶北大學校 1980 論文集 Vol.30 No.-

Effects of Thermo-Mechanical Treatment(TMT) on ageing behaviours in Al-Mg-Si alloy is investigated by means of tensile test, hardness measurements and transmission electron microscopy. The maximum 0.2% proof stress of the TMT materials in final ageing is higher by 10%∼20% than that of the two-step aged materials. The strength of TMT materials also increases more rapidly than that of two-step aged materials. The maximum 0.2% proof stress of the TMT materials with pre-ageing is higher than that of the TMT materials without pre-ageing. The strength of TMT materials increases with rising pre-ageing temperature, and it decreases with rising final-ageing temperature. Consequently, this type of TMT would have some practical significance in improving the mechanical properties of 6061 alloy.

Al-1.2%Mg_2Si擬二元系合金의 時效現象에 미치는 Cu添加의 影響

趙顯麒 慶北大學校 産業開發硏究所 1980 硏究報告 Vol.8 No.-

Effects of copper addition (up to 0.75%) on ageing phenomena in Al-1.2% Mg_2Si pseudo binary alloy were studied by means of hardness and electric resistivity measurements. The rate of age-hardening and the maximum hardness are increased by the Cu addition in the early stage of ageing at 175℃. Lowering of the hardness due to two-step ageing is relieved as the additional amount of Cu was increased, because Q' phase of a quaternary compound also precipitate in the alloys containing Cu adding to needle-like G.P. Zones.

Chilled Roll의 壽命에 미치는 Cr의 影響

趙顯麒,金東義 경북대학교 공과대학 1971 工大硏究誌 Vol.1 No.-

Cr was gradually added as much as 0.4∼0.8% to chilled cast iron to increase the surface hardness and the wear resistance by the precipitation of carbide, especially Cr-carbide in this study. Results of this experiment showed that the wear resistance of chilled cast iron roll is increased by 40∼50% with the addition of 0.6∼0.7% Cr compared to cast iron without Cr. Si-alloy was added in laddle by the three different quantity, 1kg/t, 1.5kg/t, none, in order to homogenize the brittle columnar or dendritic structure formed under the rapid solidification in metal mold or special type of mold. Among the above three cases, the best wear resistance was obtained by 1kg/t of melt inoculation.

일방향응고시킨Al-Fe(Ni)-Cr공정합금의 조직과 기계적 특성

趙顯麒,安東吉 경북대학교 산업기술연구소 1988 産業技術硏究誌 Vol.16 No.-

Eutectic and off-eutectic Al-Fe(Ni)-Cr alloys were unidirectionally solidified at the solidification rates of 0.8-20㎜/min under the temperature gradients of 80℃/㎝. And the variation of microstructure, interfacial behaviour and mechanical properties at room and elevated temperature have been investigated, the tensile strength at room temperature depends on the microstructure and volume fraction of fibers. The faster solidification rate produces the high tensile strength, but tensile strength decreases by misalignment and cellular structure of fibers at very high solidification rates the volume fraction of fibers increases with 0.5 to 1.5% Cr addition. But the transverse of Al-Ni-Cr alloys transforms from noncellular to cellular structure by 1.5% Cr addition the mean interphase spacing λ of Al-Fe-Cr and Al-Ni-Cr alloys changes in accordance with Rλ^2=12.5×10 exp (-6)㎣/min and 7.1×10 exp (-6)㎣/min respectively.

AI-Mg-Si 3원계의 AI-Mg_2Si 의2원계합금(擬二元系合金)에 있어서 Excess Mg과 Si이 기계적성질에 미치는 영향

趙顯麒,尹秉河 慶北大學校 1970 論文集 Vol.14 No.-

The mechanical properties and effects of heat treatment of Al-Mg_2Si Pseudo-Binary system are influenced so much by the solubility of Mg_2Si compound, but the excess Mg & Si gives the powful effect to that of alloy products as much as Mg_2Si. In practically, the excess Si is allowed to combine in alloy under the range of 0.2∼0.5%, because it gives the increasing of tensile strength and hardness. But the lower and upper excess Si of above range decrease the strength and hardness. And the excess Mg decrease the mechanical properties of alloy by its adding amount increasing. To product the Al-Mg_2Si Pseudo-Binary alloy, the amount of excess Mg and Si must be in range of Mg+Si%<1.0.

急冷凝固시킨 過共晶 Al―Mn 過飽和固溶體의 析出現象

趙顯麒,李基大 慶北大學校 1978 論文集 Vol.25-26 No.-

The precipitation phenomena in super saturated Al-Mn solid solutions obtained by rapid solidification was studied by means of isothermal differential measurements. Applying a Johnson-Mehl equation on these experimental results, the process of precipitation from the super saturated solid solution was kinetically analyzed. The results obtained were as follows: (1) It was found that there was a "transition" temperature in precipitation from the super saturated solutions, i. e. the transition temperature exsisted between 400°∼450℃ in cases of Al-3wt%Mn binary and Al-3wt%Mn-2wt%Zn ternary alloys, and 450°∼500℃ in cases of Al-3wt%Mn-2wt%Cu and Al-3wt%Mn-0.5wt%Si ternary alloys. (2) Activation energies for precipitation of Al_6Mn were computed to be 1.1, 1.5, 1.4 and ∼1.7 eV for the Al-3wt%Mn, Al-3wt%Mn-2wt%Zn, Al-3wt%Mn-0.5wt%Si and Al-3wt%Mn-2wt%Cu alloys, respectively.