Microstructure and Compressive Properties of Porous 2024Al-Al3Zr Composites

Abstract

Porous 2024Al-Al3Zr composites were prepared by in situ and spatial scaffolding methods. As the Al3Zr content increased from 5 wt.% to 30 wt.%, the binding of the powder in the pore wall increased and the defects in the composites decreased. The yield strength of the composites reached 28.11 MPa and the energy absorption capacity was 11.68 MJ/m3 at a Zr content of 20 wt.%, when the composites had the best compression and energy absorption performance. As the space scaffold content increased from 50% to 70%, the porosity of the composites then increased from 53.51% to 70.70%, but the apparent density gradually decreased from 1.46 g/cm3 to 0.92 g/cm3, leading to a gradual decrease in their compressive properties. In addition, by analysing the compression fracture morphology, the increase of Al3Zr will reduce the stress concentration and hinder the crack growth, while too much Al3Zr will lead to brittleness and reduce the performance.