Research on low flow stress and quantitative DRX analysis in B4C/Al composites with interfacial amorphous B2O3 layer

Abstract

Hot deformation plays a crucial role in strengthening and toughening of aluminum matrix composites, but the high hot deformation resistance and the microstructure defects generated after deformation need to be solved urgently. In this paper, a new material, B4C@B2O3/Al composites, with the low melting point B2O3 phase at the interface, has been successfully prepared and the hot deformation behavior was studied in detail. By comparison, the hot deformation resistance and activation energy of the B4C@B2O3/Al composites is significantly lower than that of the B4C/Al composites. The softening mechanism of the B4C@B2O3/Al composites is mainly dynamic recrystallization (DRX) and the critical stress of DRX is much lower for the B4C@B2O3/Al composites than for the B4C/Al composites, while the volume fraction of DRX is higher than for the B4C/Al composites. Compared with the B4C/Al composites with similar particle content, the hot deformation temperature of the B4C@B2O3/Al composites decreases, but with high strength-plasticity compatibility (with tensile strength of 560 MPa and elongation of 4.2 %). This work provides an effective method to reduce the hot deformation resistance of the B4C/Al composites and explains the micro mechanism, guiding low-stress forming of the B4C/Al composites with high volume fraction and good mechanical properties.