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.

Al-Cu-Mg 합금에 있어서의 2차 결함조직

조현기,우기도,Cho, Hyun-Kee,Woo, Kee-Do 한국현미경학회 1986 Applied microscopy Vol.16 No.2

The interrelation of secondary defects, intermediate S' phase and aging condition in Al-2.0 wt% Cu-1.1 wt% Mg alloy is studied by transmission electron microscope. The results obtained in this study are as follows. 1. High density of dislocation loops, helices and stacking faults are observed in this specimen with aging treatment. 2. The number of dislocation loops and the width of loop free zone (LFZ) are increased with aging time. 3. The intermediate S' phase precipitates and grows on the dislocations and secondary defects. 4. The misfit dislocations are formed around intermediate S' phase. 5. It is thought that the helices appear to be produced by the climb of screw dislocations, while the dislocation loops appear to be formed both by condensation of vacancies into collapsed discs and by interaction of helices with screw of opposite sign.

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-Fe 기 조직제어 합금에 있어서 E3 및 E6 공정상의 생성특성

조현기,정해룡 대한금속재료학회(대한금속학회) 1992 대한금속·재료학회지 Vol.30 No.12

The in-situ composites produced by unidirectional solidification are known by its fabrication at lower cost and its higher wettability between matrix and fibers, compared with the other composites such as F.R.M and F.R.P. The present work is aimed to examine transitional behaviour of Al-Fe based in-situ composites. Microstructure and mechanical properties at room and elevated temperatures have been studied on unidirectionally solidified Al-Fe alloy which contained additional elements such as Ti and Cr. As the solidification rate increased, Al-Al₃Fe eutectic phase changed into Al-Al_6Fe eutectic phase and morphology of the composite structure changed from the plate type into rod type in off-eutectic Al-2.23% Fe alloy. Cellular eutectic phase was formed in the coupled growth region except at extremely slow rates of solidified alloys have been improved as compared with the normally cast alloy. The Al-Al_6Fe eutectic became stronger than the Al-Al₃Fe eutecticalloy by addition of Ti and Zr elements to Al-Fe binary alloy and the Al-Al₃Fe eutectic transfered into Al-Al_6Fe at the faster solidification rate.

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.

"Al - Mg_2Si擬二元系合金의 時效擧動에 미치는 過剩Si의 영향"

趙顯麒,李基大 경북대학교 공과대학 1980 工大硏究誌 Vol.9 No.-

The improvement of age-hardenability due to excess silicon was investigated by means of hardness, electric resistivity and specific heat measurement in Al-Mg_2 Si alloys. The improvement of age-hardenability is related to the increase in the amount of solute atom clusters leading to the finer and denser distribution of needle-shaped G. P. zones. If excess silicon more than 0.2% is contained in the alloys, however all of the clusters do not always transform to G. P. zones because of those compositions considerably different from those of G. P. zones, leading to the slight improvement in age-hardenability.

Al-Zn-Mg-Cu합금의 RRA처리에 따른 相變態의 熱分析的解析

趙顯麒,金秉杰 慶北大學校 1986 論文集 Vol.42 No.-

An investigation on thermal analysis and microstructural changes of Al-Zn-Mg-Cu alloy has been carried out to examine the mechanism of the retrogression and reaging treatment which was designed to improve the stress corrosion cracking resistance of Al-Zn-Mg-Cu alloy. The results obtained were as follows ; Three heat evolution and two heat absorption ranges were observed in the specific heat measurement of specimens quenched from solution treatment temperature. This implies that aging behavior of Al-Zn-Mg-Cu alloy is similar to that of Al-Zn-Mg alloy. The rapid decrease during retrogression treatment is largely due to the dissolution of G.P. zone. Many precipitated η' and η particles contribure to the maximum strength during retrogression treatment. Redecrease of strength in retrogression treatment are due to the coarsening of particles by overaging. The increase of strength during RRA treatment are largely related to the reformation of G.P. zone by reaging treatment.

Cu-Al-Ni 합금에 있어서 시효에 따른 감쇠능의 변화

조현기,박철규 경북대학교 산업기술연구소 1987 産業技術硏究誌 Vol.14 No.-

The effects of ageing on specific damping capacity in Cu-Al-Ni alloy were carried out by the torsional pendulum testing method with the computer system. The critical range of the reverse martensitic transformation was checked by measuring adiabatic scanning calorimeter and the microstructure was observed by the optical microscope. The extent of specific damping capacity in the region of the reverse martensitic transformation increases with the amount of matrix and martensitic interface. The peak of specific damping capacity appears when the amount of martensites becomes 50% The peak of specific damping capacity decreases according to ageing due to the stabilization of martensites and the decreasing rate of specific damping capacity increases. Specific damping capacity depends on the strain amplitude and non-elastic additional strain is hysteresis type. The high level of specific damping capacity found in Cu-Al-Ni alloy is most likely to due to the reversible movement of interfacial and twin boundaries on exposure to alternating stresses.