Processing and physical properties of Al 2O 3/aluminum alloy composites

Abstract

Porous aluminum oxide (Al 2O 3) preforms were formed by sintering in air at 1200 °C for 2 h. A356, 6061, and 1050 aluminum alloys were infiltrated into the preforms by squeeze casting in order to fabricate Al 2O 3/A356, Al 2O 3/6061, and Al 2O 3/1050 composites, respectively, with different volumes of aluminum alloy content. The content of aluminum alloy in the composites was 10–40% by volume. The resistivity of Al 2O 3/A356, Al 2O 3/6061, and Al 2O 3/1050 composites decreased dramatically from 6.41 × 10 12 to 9.77 × 10 −4, 7.28 × 10 −4, and 6.24 × 10 −4 Ω m, respectively, the four-points bending strength increased from 397 to 443, 435.1, 407.2 MPa, respectively, and the deviations were smaller than 2%. From SEM microstructural analysis and TEM bright field images, the pore volume fraction and the relative density of the composites were the most important factors that affected the physical and mechanical properties. The ceramic phase and alloy phase in Al 2O 3/aluminum alloy composites were found to be homogenized and uniformly distributed using electrical and mechanical properties analysis, microstructure analysis, and image analysis.