Microstructure and properties of a HIP manufactured B4Cp reinforced highly alloyed Al-Zn-Mg-Cu-Zr aluminum matrix composite

In this study, an aluminum matrix composite with good mechanical property and excellent corrosion resistance, B4C particles (B4Cp) reinforced highly alloyed Al-Zn-Mg-Cu-Zr matrix composite, was successfully fabricated through ball-milling, cold isostatic pressing, vacuum degassing, hot isostatic pressing (HIP), homogenization, hot extrusion, solution treatment, and aging treatment. It was found that the B4C/MgAl2O4/Al was the dominant interface structure, which was coherent and enhanced the bonding between the particles and the matrix considerably, while the B4C/Al2O3/Al was the minor interface structure. The grain boundary was very clean in both T4 and T6 aging states, without aging precipitates and O element segregation. In T4 aging state, the composite exhibited superior properties, with the mass density of 2.84 g cm−3, the elastic modulus of 119.18 GPa, the yield strength of 576.08 MPa, the ultimate tensile strength of 655.27 MPa, the tensile elongation of 1.48 %, and the very low electrochemical corrosion current density of 4.4581 × 10−8 A cm−2 in 3.5 wt% NaCl water solution. The MgAl2O4 and BO3-rich interface phases, the strengthening mechanisms and the anti-corrosion mechanisms of the composite were discussed in detail. •Coherent B4C/MgAl2O4/Al was first found to be the dominant interface structure in B4Cp reinforced Al-Zn-Mg-Cu composite.•The composite exhibited 119.18 GPa elastic modulus, and 4.4581×10-8 A·cm-2 3.5 % NaCl solution corrosion current density.•The combination of so high elastic modulus and corrosion resistance had been not reported in aluminum matrix composites.•More interface BO3-rich constitute phase at T6 than at T4 aged composite might weaken the interface bonding and strength.