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AZ61-xPd (x = 0, 1 and 2 wt%) Mg합금의 미세조직 및 인장특성에 미치는 열처리의 영향
김상현 ( Sang Hyun Kim ),김병호 ( Byeong Ho Kim ),박경철 ( Kyung Chul Park ),박용호 ( Yong Ho Park ),박익민 ( Ik Min Park ) 대한금속재료학회(구 대한금속학회) 2012 대한금속·재료학회지 Vol.50 No.10
Abstract: In this study, the effect of aging treatment on the microstructure and tensile properties of AZ61-xPd (x = 0, 1 and 2 wt %) alloys were investigated. The microstructure of as-cast AZ61-xPd alloys mainly consisted of α-Mg, Mg17Al12 and Al4Pd phases. After solution treatment, most of the Mg17Al12 phases were dissolved into the Mg matrix. Thereafter, Mg17Al12 phases were finely formed and distributed near thermally stable Al4Pd phases and inside the grains through aging treatment at 220℃ during 88 hours. With the aging at 220℃, the peak aged AZ61-xPd alloys showed higher hardness than as-cast and solution treated AZ61-xPd alloys. In particular, the AZ61-1Pd alloy was optimized due to refined Mg17Al12 and Al4Pd phases. Further, the peak aging time was reduced with increasing Pd addition (>1 wt %). Tensile strength was increased by Pd addition at 25℃, 150℃, both as-cast and peak aged AZ61-xPd alloys. After aging treatment, room and high temperature tensile strength were increased more than the as-cast specimens. The AZ61-1Pd alloy especially showed the largest strength increase range. Elongation was decreased with addition Pd at 25℃ and 150℃.
반응 용탕단조한 (Al2O3 SiO2+Ni) / Al 하이브리드 금속복합재료의 제조 및 특성
김상석,박익민,김성준,최일동 ( Sang Suk Kim,Ik Min Park,Sung Joon Kim,Il Dong Choi ) 한국주조공학회 1997 한국주조공학회지 Vol.17 No.4
N/A Mechanical properties of (10%Al₂O₃·SiO₂+5%Ni)/Al hybrid composites fabricated by the reaction squeeze casting were compared with those of (15%Al₂O₃·SiO₂)/Al composites. Al-Ni intertmetallic compounds (10-20㎛) formed by the reaction between nickel powder and molten aluminum were uniformly distributed in the Al matrix. These intermetallic compounds were identified as Al₃Ni using X-ray diffraction analysis and they resulted in beneficial effects on room and high temperature strength and wear resistance. Microhardness values of (10%Al₂O₃·SiO₂+5%Ni)/Al hybrid composite were greater by about 100Hv than those of (15%Al₂O₃·SiO₂)/Al composite. Wear resistance of (10%Al₂O₃·SiO₂+5%Ni)/Al hybrid composites was superior to that of (15%Al₂O₃·SiO₂)/Al composites regardless of the applied load. While tensile and yield strength of (10Al₂O₃·SiO₂+5%Ni)/Al hybrid composites were greater at room temperature and 300℃, strength drop at high temperature was much smaller in hybrid composites.
최석규,김형일,박익민 ( Seok Kyu Choi,Hyung Il Kim,Ik Min Park ) 한국주조공학회 1991 한국주조공학회지 Vol.11 No.6
N/A This study presents the wear characteristics of Ti alloys (Pure Ti, Ti-6Al-4V, Ti-5Al-2.5Sn) fabricated by centrifugal precision casting in an Ohara dental titanium casting machine. It was found that the hardness of the surface region is higher than that of the interior region. It is considered that the oxygen adsorption in the surface region during casting, leads to the interstitial solid solution hardening. Wear resistance incerases in the order of pure Ti, Ti-6Al-4V, Ti-5Al-2.5Sn alloys. The interior hardness value increases in the same order. The specific wear rate increases with applied load and increases monotonously with sliding speed. The Fe transfer from the counterpart material was observed on the worn surface of the Ti-5Al-2.5Sn alloy. Oxidative wear occurs at low sliding speeds and mechanical fracture wear occurs at high sliding speeds.