CuAlNi 형상기억합금의 압연조건에 따른 미세조직변화

양권승 조선대학교 생산기술연구소 2005 生産技術硏究 Vol.27 No.1

Shape memory alloy with 83Cu-13Al-4Ni(wt%) composition was prepared by cross rolling method and phase transformation characteristics were investigated. Transformation temperatures are almost the same in specimens prepared by both hot-rolling and cross rolling at 900℃. but. in specimen prepared by cross rolling at 350℃, its transformation temperature shows the change of 40℃ and a large hysteresis. Indesirable tweed-like structure is observed in aged specimen at 200℃ after a cross rolling at 350°C. On aging the specimen prepared by cross rolling, G.P zone was formed easier than that of γ2 phase. This phase was transformed to plate-like θ' phase during aging.

構造用鋼의 熱處理가 機械的性質에 미치는 影響

梁權承 조선대학교 생산기술연구소 1982 生産技術硏究 Vol.1982 No.-

The influence of heat treatment on the mechanical properties of structural steel in the austenitizing temperature range between 870℃∼1200℃ was studied. The results obtained from this study are summarized as follows. 1. When the austenitizing temperature was high, strength and toughness decreased but the impact energy increased. 2. When tempering was at 400℃, the influence of austenitizing temp on hardness was great. And in case of strengths the difference between them according to austenitizing temperatures grew wide as tempering temp increased. But elongation was little influenced. 3. When the austenitizing time under constant austenitizing temperature was long, hardness and impact energy decreased.

2相耐熱鋼의 임계영역(α+γ)에서의 加熱維持時間이 定常크리이프에 미치는 영향

梁權承,郭士濩 조선대학교 기초과학연구소 1985 自然科學硏究 Vol.8 No.1

In this study the effects which the holding time in the intercritical region(α+γ) of 1000℃ has on the steady state creep of 6543 steels(12Cr-2Mo) and 6546 steels(12Cr-2Mo-2Ni) were investigated. These steels were developed for elevated temp. tubing applications by Climax Molydenum Co in America in 1982. The relations between the steady state creep and the redistribution of solute atoms and microstructure changes during intereritical anneal and creep testing according to holding time were in particular studied. The results obtained are summarized as follows: 1) 6546 steels (2% Ni added) maintained higher creep strength than 6543 steels (free of Ni) in short-term creep test while in the longer-term 6543 steels surpassed 6546 steels. It seems that nickel is effective for the formation of martensite responsible for the rise of short-term strength, and not for the longer-term creep strength. This is significant in the light of economy for the development of high temp. Materials. 2) In 6543 steels tensile and yield strength are at their best at the 1.5 hr holding time and afterwards decrease progressively. But in 6546 steels tensile property doesn't change much upto 30 hr holding, while yield strength tends to decrease from the 15 hr holding time. That's attributed to coarsening of grains, It is assumed from these facts that the effect of graim size on the mechanical properties is greater in yield strength than tensile strength. 3) 6543 steels lose their strengthening effects through coarsening of grains as the holding time lasts longer than 1.5 hr. 4) It is assumed that for the precipitates of Laves phase in this 12Cr-2Mo steel the concentraion differences between the α and γ phase are decisive and that its precipitation occurs initially in the ferrite. 5) In the duplex structure steels, Mo, Cr, etc. are partitional rich in ferrite phase during creep test and cause the precipitation of M_23C_6, Fe_2Mo, M_6C, etc., which contributes to strengthening the matrix. But martensite phases are dissolved during creep test. It is considered that the long-term creep strength is achieved more by the strengtheining of ferrite structure than that of martensite. 6) 6543C steel solution-treated at 1000℃ for 1.5 hr revealed the strongest creep rupture strength of all 6543 steels at 550∼600 ℃. That's because the precipitates of M_23C_6, Fr_2Mo, M_6C, etc. are so large in numbers and fine, and their stability is excellent.

중학교 과학영재교육을 위한 심화학습 프로그램의 개발 및 적용-빛의 반사와 굴절 단원을 중심으로

양권승,조중현,오희균 全南大學校 師範大學 科學敎育硏究所 2001 科學敎育硏究誌 Vol.25 No.1

Gifted education has been emphasized in two views , one is self-realization of individual and the other is educating the talented requisite for the knowledge-based future society. In order to vitalize the gifted education, enrichment programs must be developed along with the education system. In this research literature were reviewed for developing the study resource adequate for the gifted in science. The direction of the resource-development was established on the basis of combination of several models such as Enrichment Triad Model (Renzulli,1978), Self-directed learning Model(Treffinger,1982) and Creative Problem Solving Model (parnes, 1967). The objective of resource development is to raise the creativity and problem solving ability of students through their various experiences in interesting studies. The scope of resource development is "Reflection and Refraction of the light" of grade 7 in the 7-th curriculum. Developed resources were applied to the students of Sun Cheon gifted c1ass, advance science c1ass of Yeong Gwang Hong Nong middle school. The students were instructed to do creative and self-directed study activities. The feedbacks from students after the application of developed resources were 1. Contents of the program were appropriate in view of the difficulty and the interconnectivities of contents 2. Procedure was interesting and it was helpful to raise the ability in self-directed study and creative problem solving. 3. Most students hope to take part in the science gifted education program with various topics. This developed resource can be utilized not only in many kinds of gifted classes, advanced curriculum but also as individualized resources for improving creative problem solving ability. Teachers in charge of the gifted education, can have the opportunity to participate in development of abundant resources in various areas

CuAlNi 형상기억합금의 시효처리에 따른 상변태 거동

양권승,강조원 ( G . S . Yang,J . W . Kang ) 한국열처리공학회 1993 熱處理工學會誌 Vol.6 No.4

This research was performed to investigate the transformation behavior and shape memory effect of Cu13.5Al-4.5Ni(wt%) alloy with various aging temperature and time. The results obtained in this study are as follows: Transformation temperature was very increased when aging temperature is at 250℃. The variation of transformation temperature in first reverse transformation cycle and second was very significant, but there was little difference in case of 2nd and 3rd, Transformation temperature at various aging temperature was increased with increasing of aging temperature and time. Microvickers hardness was increased with increasing of aging temperature and time. It was found that α and γ₂phase were created by aging of long time at high temperature.

CuZnAI형상기억합금의 변태온도에 미치는 열사이클 및 기계적성질 변화

양권승,박진성,강조원,Yang, Gwon-Seung,Park, Jin-Seong,Gang, Jo-Won 한국재료학회 1994 한국재료학회지 Vol.4 No.5

소량의 misch metal과 Zr을 함유한 CuZnAI형상기억 합금의 변태온도에 미치는 열사이클 및 기계적 성질 변화에 대하여 고찰하였다. 합금원소 첨가에 따라 결정립에 매우 미세화 되었으며 용체화 처리후 100~$350^{\circ}C$구간에서 경도값 변화를 조사하기 위하여 post quench aging과 step quench aging처리한 결과 $200^{\circ}C$와 $250^{\circ}C$에서 최고의 경도값을 나타냈다. $M_f$온도이하에서 인당시험한 결과 파단강도와 연실율은 결저립이 미세할수록 증가하는 경향을 보였다. 또한 파단강도는 as quenching처리한 경우보다 post quench aging처리한 경우에 보다더 증가하였다. $\beta$-상에서의 시효는 $M_s$온도를 강하시켰으며 마르텐사이트상에서의 시효는 $A_s$ 온도를 증가시켰다. post quench aging 에 따른 $A_s$의 변화는 $\beta$에서의 회복율에 기여하였으며 변태온도 ($A_s-M_s$)히스테리시스는 열사이클에 의하여 증가하는 경향을 보였다. The effects of transformation temperature and mechanical properties by thermal cycle of CuZnAl shape memory alloy with a small of misch metal and Zr contents were investigated. The addition of misch metal and Zr was very effective for reducing the grain size. After solution treatment, the specimens were post-quench aged or step quenched at $100^{\circ}C$ to $350^{\circ}C$ for variation of Rockwell hardness value. It was found that the Rockwell hareness value was very increased at $200^{\circ}C$ and $250^{\circ}C$. The fracture strength and ductility have been significantly increased with the increase of misch metal conten when tensile tested below $M_f$ temperature. Also, the fracture strength has been more increased in the case of post quench aging treatment than that of the as-quenching treatment. Aging of the $\beta$-phase decreases the $M_s$ temperature, but that of the martensite phase increases the $A_s$ temperature. The change in $A_s$ temperature with post-quench aging can be attributed to recovery of order in the $\beta$phase. The hystersis of transformation temperature ($A_s-M_s$) has an increasing tendency by thermal cycles.

상용 AZ31B Mg합금 판재의 어닐링에 따른 집합조직 변화 및 결정립 이상 성장

양권승 ( G. S. Yang ),윤성식 ( S. S. Yoon ),장우양 ( W. Y. Jang ),강조원 ( J. W. Kang ) 한국열처리공학회 2008 熱處理工學會誌 Vol.21 No.6

티오요소를 이용한 삼조광업 정광으로부터 은 용출 최적화

양권승 ( Gwon Seung Yang ),김봉주 ( Bong Ju Kim ),최낙철 ( Nag Choul Choi ),박천영 ( Cheon Young Park ) 한국광물학회 2013 광물과 암석 (J.Miner.Soc.Korea) Vol.26 No.1

티오요소를 사용하여 삼조광업 정광으로부터 온을 친환경적으로 용출시키고자 하였다. 상조광산의 광석은 황철석, 황동석, 방연석, 유비철석, 섬아연석 등과 같은 광석광물들로 구성되어 있다. 티오요소 용출실험에는 750℃에서 소성시킨 소성정광을 사용하였다. 다양한 실험조건으로 용출실험을 수행한 결과, 본 실험 조건 중 가장 높은 은 용출율이 나타나는 조건 중 가장 높은 은 용출율이 나타나는 조건은 티오요소 농도 0.8 g일 때, 황산 제2철 0.425 g일 때, 그리고 용출온도 60℃일 때였다. 광액농도 10%일 때 은 용출율 91.5%를 얻었다. 그러나 고체 잔유물에 대해서 XRD 분석을 수행한 결과, 은 용출율이 사장 높은 고체 잔유물들에서 황철석, 방연석, 적철석 등이 나타났다. 이러한 결과가 미루어 볼 때 고체 잔유물에 포함된 은은 회수하지 못하고 소실된 것으로 예상된다. This study was carried out to test the possibility of using an environmentally friendly method of leaching silver concentrate from the Samjo mine. The Samjo mine ore contained minerals such as pyrite, chalcopyrite, galena, arsenopyrite, and sphalerite. The concentrate samples tested with the thiourea solution were roasted at 750℃. The results of different experimental conditions showed that the highest silver leaching rate was obtained when the concentration of thiourea was at 0.8 g with ferric sulfate at 0.425 g and the leaching temperature at 60℃. The Ag leaching rate obtained was 91.5% at a pulp density of 10%. However, in the XRD analysis, peaks of pyrite, galena, and hematite were still found in the leached solid residues in which the Ag leaching rate was the highest, it is expected that the unrecovered silver in the solid residue can be lost.

Kelex100로부터 구리입자 분말 합성

조종상,양권승,P.R Taylor 한국결정성장학회 1998 韓國結晶成長學會誌 Vol.8 No.1

구리입자를 코딩한 분말 합성은 Kelex 100 solvent extraction으로부터 silica powder에 수소압력 stripping copper에 의하여 생성하였다. Solvent extraction의 범위내인 일정한 조건에서 loading level과 stripping rate등을 재생하였으며 stripping copper kinetics는 divalent상태에서 metallic 상태로 감소하면서 silica 입자에 침적하였다. Copper들은 seed 입자에 heterogeneous 핵을 형성하면서 이들은 agglomeration 상태로 생성되었고 불균일한 분말로 형성하였다. A composite copper coated powder was generated by pressure hydrogen stripping copper from Kelex 100 solvent extractant in the presence of silica powder. Within the limitation of solvent extraction under constant conditions, both loading level and stripping rate were reproducible. The stripping copper kinetics are reduced from a divalent state to a metallic state and then deposited on the surface of the silica powder. Copper nucleates heterogeneously on the seed particles. They are giving an agglomerated and non - uniform powder.

Cu-Al-Ni계 SMA합금 리본의 안정화 및 열처리

장우양,양권승,강조원 조선대학교 생산기술연구소 2003 生産技術硏究 Vol.25 No.2

In order to clarify the effect of the composition and wheel speed on the phase stability of parent phase, the Cu-AI-Ni based alloy ribbons with different Al content were manufactured by rapid solidification process at various wheel speed. The effect of heat treatment on the microstructure and transformation characteristics of the ribbons with fiber structure have been studied by using OM, SEM, TEM, XRD and DSC. The parent phase was retained in the ribbon fabricated at a faster wheel speed even the same composition or in the ribbon contained higher Al content even at the same wheel speed. As flash-heating temperature increased from 750℃ to 850℃, the retained parent phase disappeared and peak of martensite phase only appeared. When ribbon A5 was aged at 60℃ for 10, 24, 48 and 72 hour, no remarkable changes was observed with increasing in aging time. Transformation temperatures in ribbon AS aged at 60℃ for 10, 24, 48 and 72 hour were lower than those in ribbon A5 in as-spun ribbon. When the ribbon A5 was aged at 100℃ for 10, 24, 48 and 72 hour, both retained parent phase and martensite were observed in the ribbon A5 aged for 10 and 24 hour observed. Microstructure of cross-sectional surface of ribbon aged at 100℃ for 72 hour was changed to columnar structure and transformation temperature rose only ribbon A5 aged for 72 hour.