Fabrication of hypereutectic Al–Si alloy with improved mechanical and thermal properties by hot extrusion

Ding，Chao1,2; Hao，Huali3; Lu，Zhouguang2; Yu，Changyang2; Wu，Xinzhi2; Yu，Peng4; Ye，Shulong1,2

2023-08-01

10.1016/j.matchar.2023.113026

Materials Characterization   影响因子和分区

1044-5803

1873-4189

Silicon phase in hypereutectic Al–Si powders appears as primary Si and eutectic Si. Due to the poor thermal stability of eutectic Si, the material suffers from pores, stress concentration and dislocation packing during hot extrusion process, resulting in low density and poor thermal properties. In order to eliminate the eutectic Si, a heat treatment is conducted on Al–20Si powder before hot extrusion. Because of the Ostwald ripening effect, the eutectic Si and dislocations in the powder are replaced by isolated Si lumps and a clear Al matrix. As a result, the formability and thermal properties of the material are greatly improved. The extruded samples made from the treated powder present high relative densities 99.7–100%, ultimate tensile strength (UTS) 167–170 MPa, elongations 8.8–10.8% and thermal conductivities (TCs) 191–195 Wm K and low coefficient of thermal expansions (CTEs) 13.8–14.5 × 10/K. The excellent mechanical and thermal properties are attributed to the elimination of eutectic Si from the treated powder and as-extruded alloys. In addition, hot extrusion introduces in-situ AlO in the Si surface, Al grain boundary and Al grains, which is beneficial to reducing and stabilizing the CTE of the material. Moreover, it hinders Ostwald ripening and thus growth of the Si particles during the service of the material.

Hot extrusion Hypereutectic Al–Si alloys Mechanical properties Microstructure Thermal properties

SCI ; EI

英语

通讯

National Key Research and Development Program of China[2021YFB3701900];National Natural Science Foundation of China[52104362];

Materials Science ; Metallurgy & Metallurgical Engineering

Materials Science, Multidisciplinary ; Metallurgy & Metallurgical Engineering ; Materials Science, Characterization & Testing

WOS:001007126800001

ELSEVIER SCIENCE INC

20232214170383

Alumina ; Aluminum ; Aluminum alloys ; Aluminum oxide ; Eutectics ; Extrusion ; Grain boundaries ; Silicon alloys ; Tensile strength ; Thermal conductivity ; Thermodynamic stability

Metallography:531.2 ; Aluminum:541.1 ; Aluminum Alloys:541.2 ; Nonferrous Metals and Alloys excluding Alkali and Alkaline Earth Metals:549.3 ; Thermodynamics:641.1 ; Inorganic Compounds:804.2 ; Materials Science:951

MATERIALS SCIENCE

2-s2.0-85160441090

Scopus

1.Faculty of Materials Science,Shenzhen MSU-BIT University,Shenzhen,518172,China
2.Department of Materials Science and Engineering,Southern University of Science and Technology,Shenzhen,518055,China
3.School of Civil Engineering,Wuhan University,Wuhan,420072,China
4.Shenzhen ElementPlus Material Technology Co. Ltd.,Shenzhen,518107,China

Ding，Chao,Hao，Huali,Lu，Zhouguang,等. Fabrication of hypereutectic Al–Si alloy with improved mechanical and thermal properties by hot extrusion[J]. Materials Characterization,2023,202.

Ding，Chao.,Hao，Huali.,Lu，Zhouguang.,Yu，Changyang.,Wu，Xinzhi.,...&Ye，Shulong.(2023).Fabrication of hypereutectic Al–Si alloy with improved mechanical and thermal properties by hot extrusion.Materials Characterization,202.

Ding，Chao,et al."Fabrication of hypereutectic Al–Si alloy with improved mechanical and thermal properties by hot extrusion".Materials Characterization 202(2023).