Microstructure and compressive behavior of lamellar Al₂O₃p/Al composite prepared by freeze-drying and mechanical-pressure infiltration method

Abstract

Infiltrated molten Al matrix by mechanical-pressure infiltration method into the ceramic scaffold prepared by freeze-drying technology could prepare dense lamellar Al matrix composites without damage of the biomimetic microstructure of the scaffold. However, the investigation of lamellar Al matrix composites prepared by freeze-drying and mechanical-pressure infiltration method has not been fully understood yet. In the present work, the Al2O3 scaffold with pearl layer structure was prepared by freezing-dry method, and eventually the lamellar Al2O3p/Al composite was fabricated by mechanical-pressure infiltration method. The Al matrix was infiltrated well into the large pores of the Al2O3 scaffold, and the lamellar structure of the Al2O3 was well preserved. The hardness of the lamellar Al2O3p/Al composite was isotropic in transvers and perpendicular directions. However, the compressive strengths of the lamellar Al2O3p/Al composite were significant anisotropic while the compressive strength in transvers direction was 127.7% higher than that in the perpendicular direction, indicating the integrality of the lamellae microstructure (especially the bridging layers). Due to the mismatched deformability, weak debonding was observed between Al and Al2O3p/Al layers in the fracture surface of the lamellar Al2O3p/Al composite. It indicates that the interfacial bonding between Al and Al2O3p/Al layers is rather strong, which is beneficial for higher strength in transvers direction but lead to lower strength in perpendicular direction.

Uniaxial Compressive Behavior of AA5083/SiC Co-Continuous Ceramic Composite Fabricated by Gas Pressure Infiltration for Armour Applications

“…Though the pressureless infiltration method [22,23] is economical and has the benefits of easy industrialization, pressure infiltration [24,25] is preferred for the manufacture of C4 due to its lower infiltration time, performance, and efficiency. A recent study by Zhang et al [26] reported that mechanical-pressure infiltration method was effective for producing Al 2 O 3 /Al based materials for scaffoldings. The study also reported that the pressure infiltration technique enhanced the interfacial bonding between Al 2 O 3 layers and the infiltrant Al alloy.…”