Effect of addition of boron and B4C coated diamond on the microstructure and compressive behaviour of porous aluminium composites

Abstract

Owing to the growing demand for lightweight materials in automotive and aerospace applications, porous aluminium composites are studied in-depth due to their high strength-to-weight ratio, higher stiffness and good compressive properties. The studies include enhancing their strength by the inclusion of strengthening reinforcements. In this study, the effect of boron addition in the matrix combined with uncoated diamond as reinforcements was compared with the effect of B₄C coated diamond on the microstructure, density, porosity and compressive properties of porous AlSnMg matrix composites. The addition of boron in the matrix combined with using uncoated diamond showed least significant improvement in properties while the addition of B₄C coated diamond revealed better results. The microstructure of porous composites revealed that the boron addition insignificantly affected the bonding at the interface of matrix and uncoated diamond reinforcement comparatively B₄C coated diamond improved the bonding at the interface of aluminium matrix and diamond. As a result, the higher densities and compressive strength of 39.97 MPa and energy absorption capacity of 13.2 MPa were acquired for porous Al composites with 10 wt.% of B₄C coated diamond suggesting the use of coated diamond in porous aluminium for enhancing their strength in applications as fillers in light weight structures for automotives.