Fe 함유 Al-10Si-Mg 주조 합금의 미세조직, 인장 및 열전도도 특성에 미치는 과열 처리의 효과

• Published in: 대한금속·재료학회지, 62(5) Vol. 62; no. 5; pp. 402 - 410
• Main Authors: 장진혁, Jin-hyeok Jang, 강태훈, Tae-hoon Kang, 어광준, Kwang-jun Euh, 조영희, Young-hee Cho, 이기안, Kee-ahn Lee
• Format: Journal Article
• Language: Korean
• Published: 대한금속재료학회 01.05.2024; 대한금속·재료학회
• Subjects: Al-10Si-Mg; Fe addition; Microstructure; Superheating; Tensile Property; Thermal conductivity; 재료공학
• ISSN: 1738-8228; 2288-8241
• DOI: 10.3365/KJMM.2024.62.5.402

In this study, we designed and manufactured a new Fe-bearing Al-10Si-Mg casting alloy (F alloy) and investigated its microstructure, mechanical properties, and thermal conductivity. Two types of Fe-bearing Al-10Si-Mg alloys were used: the Conventional-F alloy, injected at 720℃ and cooled by water quenching, and the Superheated-F alloy, heated to 820℃ and maintained at that temperature for 1 hour. Subsequently, it underwent a degassing process at 720℃ before being cooled by water quenching. Both the Conventional-F alloy and the Superheated-F alloy exhibited dendritic microstructures and Fe-intermetallic compounds. The Secondary Dendrite Arm Spacing (SDAS) of the Conventional-F alloy measured 32.4 μm, whereas the Superheated-F alloy measured 28.6 μm. Additionally, the average eutectic Si sizes were 10.3 μm for the Conventional-F alloy and 7.7 μm for the Superheated-F alloy. Fe-rich IMCs were observed in the eutectic region, with their size decreasing due to the superheating treatment. Tensile tests at room temperature were conducted at a strain rate of 10 -3 /s. The Conventional-F alloy exhibited a yield strength (YS) of 93.4 MPa, ultimate tensile strength (UTS) of 183 MPa, and an elongation (El.) of 6.4%. Conversely, the Superheated- F alloy displayed a YS of 115.4 MPa, UTS of 218.2 MPa, and an El. of 5.1%. The mechanical properties notably improved with the superheating treatment. Regarding thermal conductivity, the Conventional-F alloy exhibited 114.9 W/m·K, while the Superheated-F alloy displayed 153.7 W/m·K. This represents a roughly 14% increase compared to the thermal conductivity of the commercial Al-10Si-Mg material (Silafont36: 135.1 W/m·K). The effects of the Superheating Treatment on microstructural characteristics, deformation behavior, and thermal conductivity of the Fe-bearing Al-10Si-Mg casting alloys were discussed. (Received 12 December, 2023; Accepted 18 January, 2024)