Effect of Y2O3 on thermophysical parameters and mechanical properties of Al-Al2O3 composites and compatibility with high temperature Al-Si alloys

Abstract

Al-Al _2 O _3 is a crucial encapsulation composite used in solar thermal storage systems. This study utilized Al and Al _2 O _3 powders as raw materials, with Y _2 O _3 serving as a sintering aid, to prepare Al-20Al _2 O _3 -xY _2 O _3 composites (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0 wt%) through the cold pressure sintering method. The latent heat, thermal conductivity, and bending strength of the Al-20Al _2 O _3 -xY _2 O _3 composites were measured. The compatibility of the composites with Al-12 wt%Si alloys was analyzed. Furthermore, the relationships between thermophysical parameters, mechanical properties, compatibility, and microstructure were explored. The oxidation mechanism of Al and the wetting angle of the composites with Al-12Si were simulated using LAMMPS software. It was concluded that with an increase in Y _2 O _3 content, the bending strength, thermal conductivity, and compatibility of the composites initially increased and then decreased. The Al-20Al _2 O _3 -0.2Y _2 O _3 composite exhibited the least porosity, highest bending strength (76.32 MPa), and thermal conductivity (46.82 W/(m·K)). In compatibility testing, the diffusion distance of Si atoms was shortest (90 μm) in the Al-20Al _2 O _3 -0.2Y _2 O _3 composite. Moreover, this composite had the largest wetting angle (88°) with the Al-12Si alloy, resulting in good compatibility between them.

Keywords

• Al-20Al2O3-xY2O3
• LAMMPS
• thermal conductivity
• bending strength
• compatibility