합금화용융아연도금강판의 미세파괴거동에 대한 In-situ 관찰

문현수,부현덕,추용호,안병국,김영근,안행근,Mun Hyun-Su,Bu Hyun-Duck,Chu Yong-Ho,Ahn Byung-Kuk,Kim Young-Geun,Ahn Haeng-Keun 한국재료학회 2004 한국재료학회지 Vol.14 No.9

In-situ observation in SBM on the microfracture behavior of coating layer was performed for GA steel sheets that have various Fe contents and thickness of coating layer. In case of cross sectional side of coating layer that was in a tensile stress state during bending, fine perpendicular crack pre-induced during galvannealing grew and propagated rapidly toward the coating surface with the increase of strain. And then it grew and propagated along the ${\Gamma}/Fe$ matrix interface, and combined with the nearest another perpendicular crack. Consequently, flaking occurred. The more Fe content and thickness of coating layer increased, the more average crack interval and flaking resistivity increased. Exfoliation was little observed at coating surface in a tensile stress state.

Sn-4.0wt%Ag-0.5wt%Cu 솔더 접합계면의 강도특성과 미세파괴거동에 대한 In-situ관찰

이경근,최은근,추용호,김진수,이병수,안행근,Lee, Kyung-Keun,Choi, Eun-Geun,Chu, Yong-Ho,Kim, Jin-Soo,Lee, Byung-Soo,Ahn, Haeng-Keun 한국재료학회 2008 한국재료학회지 Vol.18 No.1

The micro-structural changes, strength characteristics, and micro-fractural behaviors at the joint interface between a Sn-4.0wt%Ag-0.5wt%Cu solder ball and UBM treated by isothermal aging are reported. From the reflow process for the joint interface, a small amount of intermetallic compound was formed. With an increase in the isothermal aging time, the type and amount of the intermetallic compound changed. The interface without an isothermal treatment showed a ductile fracture. However, with an increase in the aging time, a brittle fracture occurred on the interface due mainly to the increase in the size of the intermetallic compounds and voids. As a result, a drastic degradation in the shear strength was observed. From a microshear test by a scanning electron microscope, the generation of micro-cracks was initiated from the voids at the joint interface. They propagated along the same interface, resulting in coalescence with neighboring cracks into larger cracks. With an increase in the aging time, the generation of the micro-structural cracks was enhanced and the degree of propagation also accelerated.

SiCp 입자강화 Al 복합재료의 내열 및 마모특성

김석원(Sug Won Kim),김완기(Wan Ki Kim),우기도(Kee Do Woo),안행근(Haeng Keun Ahn) 한국주조공학회 2000 한국주조공학회지 Vol.20 No.6

N/A Al matrix composites as the most promising MMCs can be expected to be excellent engineering materials in the nearest future. So as to improve material properties of composite, many manufacturing processes have been developed. Among them, squeeze casting process which offers fine microstructure and near-net-shape is one of the most successful MMCs manufacturing processes. But, in case of with subsieve size particles (under 44㎛), it is very difficult to homogeneously distribute particles in matrix of Al matrix composite by various casting processes, including squeeze casting used so far. Duplex process which was developed in previous study was used to distribute the particle of subsieve size more homogeneously in matrix of Al matrix composite. Microstructures, wear and heat resistance characterization of Al-Si-Cu-Mg-(Ni)/SiCp manufactured by duplex process were examined to clarify the effect of manufacturing conditions, particle size of reinforcement and alloying elements. Al matrix composites reinforced with SiCp(10㎛) have the lowest wear amount among composites reinforced with 3㎛, 5㎛ and 10㎛ SiCp. The wear amount of Al matrix composites with 10wt% SiCp(3, 5, 10㎛) was decreased according to the increase of the sliding speed because abrasive wear takes place at high sliding speed of 4㎧ and worn debris with block type occurs at low sliding speed of 1㎧. As for heat resistance, it is made clear that remarkable heat resistance property can be obtained by addition of Ni element in Al matrix composites.

MBE법으로 성장시킨 InxGa₁_xAs (x=0.02) 에피층에서의 Photo reflectance에 관한 연구

김인수(In-Soo Kim),이정열(Jung-Yeul Lee),배인호(In-Ho Bae),김상기(Sang-Ki Kim),안행근(Haeng-Keun Ahn),박성배(Sung-Bae Park) 한국진공학회(ASCT) 1996 Applied Science and Convergence Technology Vol.5 No.2

반절연성 GaAs(100) 위에 Molecular Beam Epitaxy(MBE)법으로 In의 조성을 0.02으로 일정하게 하여 성장시킨 In_xGa_(1-x)As/GaAs의 photoreflectance(PR) 스펙트럼 특성을 측정하였다. 기판과 에피층의 PR 신호가 분리되어 관측되었으며, 띠간격 에너지 (E。)는 약 1.40eV로써 Pan의 식에 fitting한 결과 약 8meV의 차이가 생겼다. 이는 에피층과 기판의 격자부정합(lattice mismatch)으로 인해 파생되는 계면에서의 응력 (stress)이 그 요인으로 이것이 시료 성장시 결정성에 영향을 미치고 있음을 확인할 수 있었다. 또한, ln_(0.02)Ga_(0.98)As 에피층은 온도 의존도가 낮고 광흡수 효율이 크며 200K 이상의 온도에서 활성화되는 것으로 분석되었고, 성장 온도보다 낮은 온도 400℃로 열처리시킨 경우에 PR 신호 분리가 가장 뚜렷하였으며, 이때 결정성 또한 향상됨을 알았다. We measured photoreflectance spectrum characteristics of InGaAs grown by MBE method on semi-insulating GaAs. The PR signal splitting of substrate and epilayer was observed. The band gap energy was about 1.40 eV. It make to 8 meV difference when it is fitted by Pan's equation. The reason is stress on the interface, which is due to lattice mismatch between epilayer and substrate. We became to know that reason influence crystalline on growing sample. In InGaAs epilayer, temperature dependency is low. The efficiency of photo absorption is high and activate over 200K. In this case when it is annealed at 400℃ below growing temperature, PR signal splitting is remarkable and crystalline is inhanced.

Silicate계 유리와 알루미나와의 젖음성

안병국,안행근,김학신 全北大學校 1993 論文集 Vol.36 No.-

For the fundamental knowledge about the behavior of glass solder in the case of joining of ceramics, the wettability of glass on alumina were measured by sessile drop method. SiO_2-CaO-Al_2O_3 glasses were selected as examples of glass, and alumina of the various compositions were used as substrates. Contact angle of glass on 99% alumina didn't decrease with time at elevated temperature, while 92% alumina showed time-dependent property. It was the reaction between glass and 92% alumina that contact angle of glass on 92% alumina decreased with time.

무가압 침투법에 의해 제조된 Al-5Mg-X(Si,Cu,Ti)SiCp 복합재료의 조직 및 마멸특성

우기도,김석원,안행근,정진호 한국주조공학회 2000 한국주조공학회지 Vol.20 No.4

Metal matrix composites(MMCs) reinforced with hard particles have many potential application in aerospace structures, auto parts, semiconductor package, heat resistant panels, wear resistant materials and so on. In this work, the effect of SiC partio sizes(50 and 100㎛) and additional elements such as Si, Cu and Ti on the microstructure and the wear property of Al-5Mg-X(Si, Cu, Ti)/SiC_p composites produced by pressureless infiltration method have been investigated using optical microscopy, scanning eletron microcopy(SEM) with EDS(energy dispersive spectrometry), hardness test, X-ray diffractometer(XRD) and wear test. In present study, the sound Al-5Mg-X(Si, Cu, Ti)/SiC_p(50 and 100㎛) composites were fabricated by pressureless infiltration method. The Al-5Mg-0.3Si-O.1Cu-O.1Ti/SiC_p composite with 50㎛ size of SiC particle has higher hardness and better wear property than any other composite with 100㎛ size of SiC particle produced by pressureless infiltration method. The hardness and wear property of Al-5Mg/SiC_p(50 and 100㎛) composites were enhanced by the addition of Si, Cu and Ti in Al-5%Mg matrix alloy.

Ti (Nb) 첨가 IF 강의 집합조직 형성에 미치는 P 첨가의 영향

이상호,이병영,이오연,안행근 대한금속재료학회(대한금속학회) 1994 대한금속·재료학회지 Vol.32 No.7

The effect of P addition on the formation of recrystallization texture in intersititial free (IF) extra low carbon steel sheet has been investigated. IF steel sheet exhibited high r-value texture (more specifically, {554}$lt;225$gt; type texture) independent of heating rate at the final annealing after cold rolling. Ti-P and Nb-P steels, however, enhanced near {100} grain provided that slow heating cycle, i.e., box annealing cycle was applied, and therefore r-value (deep drawability) is deteriorated for these steels. On the other hand, when rapid heating cycle, i.e., continous annealing cycle was applied for these steels, the growth of uncleated {100} grain was inhibited by large amount of recrystallized {111} grains, developing strong {111}({554}$lt;225$gt;) recrystallization texture. Futhermore, the {111} components increased with low finishing temperature at 800℃ in the hot rolling stage, was attributed to coarse precipitates of Fe(Nb, Ti)P in the matrix. It is considered that lowering the hot rolling temperature and adding the Ti and Nb can effectively reduce the grain boundary segregation of phosphorus, in the Fe-Ti(Nb)-P alloy, cause a decrease coarse precipitates on the grain boundary.