Preparation of High-Strength Al–Mg–Si/Al_2O_3 Composites with Lamellar Structures Using Freeze Casting and Pressureless Infiltration Techniques

Lamellar porous alumina scaffolds with the initial solid loadings of 20, 25, and 30 vol% were prepared by freeze casting using 5 lm alumina powders. With the addition of 3 wt% Mg O–Al2O3–Si O2 nanopowders in a eutectic composition as sintering aid, the maximum compressive strength of the sintered scaffolds reached(64 ± 2) MPa after sintering at 1,773 K for 2 h. The lamellar porous scaffolds were then filled with a molten Al–12Si–10 Mg alloy(in wt%)by pressureless infiltration at 1,223 K in a N2 atmosphere, yielding the shell-like structure of the composites. The compressive strength of the upper part composite with the initial 30 vol% solid loading reached(1,190 ± 50) MPa, which was about 3.5 times as large as that of the matrix alloy.

Preparation of High-Strength Al-Mg-Si/Al2O3 Composites with Lamellar Structures Using Freeze Casting and Pressureless Infiltration Techniques

Biomimetic Metal-matrix composites Porous materials