| 학회 | 한국재료학회 |
| 학술대회 | 2015년 봄 (05/14 ~ 05/15, 구미코) |
| 권호 | 21권 1호 |
| 발표분야 | D. 구조 재료 |
| 제목 | The effect of Si size on the mechanical and thermal properties of Al-S-Cu-Mg foundry alloys |
| 초록 | The Al-Si systems are most commonly used as aluminum foundry alloys over a wide range of mechanical and thermal applications where strength at elevated temperature is important. Especially, the Al-Si foundry alloys with Cu and Mg additions are widely used in automotive engine compartments, such as engine blocks, cylinder heads, and pistons, because of their good fluidity and castability. Addition of silicon provides good wear resistance, low thermal expansion coefficient and high heat transfer coefficient. Cu and Mg additions in the Al-Si system are known to promote the precipitation of secondary phases by a simple heat treatment and thereby improve the mechanical properties. The purpose of this study is to describe and examine the way to enhance the thermal properties of the Al-Si-Cu-Mg alloy while maintaining the mechanical strength after heat treatment. In addition, the comparative measurements of as-cast and heat-treated specimens, such as, the thermal diffusivity and specific heat, have been carried out for knowing the influence of the heat treatment on the thermal conductivity, and the correlation between the thermal properties and the microstructure has been shown in this study. The microstructure of the Al-9.7Si-0.7Cu-0.4Mg alloy solidified by different cooling rates was reported in this study and solution heat treatment followed by aging treatment was carried out for the effects of heat treatment on mechanical and thermal characteristics. The solution treatment was performed at 535°C for 6 h and then the specimens were cooled by water quenching. The samples were aged at 180°C or 190°C for 1-10 h. By heat treatment, the long needles of eutectic silicon particles were broken down into smaller fragments and then gradually spheroidized. Spheroidizing of the eutectic silicon particles has found to improve the tensile strength and thermal diffusivity of the alloy. In particular, as increasing the aging temperature of Al-Si-Cu-Mg alloy from 180°C to 190°C, the 3% higher thermal conductivity was achieved. |
| 저자 | Se-Weon Choi1, Shinji Kumai2 |
| 소속 | 1KITECH, 2TITECH |
| 키워드 | Al-Si-Cu-Mg alloy; Casting; Heat treatment; Mechanical properties; Thermal property |
