Enhanced strength-ductility synergy in a boron carbide reinforced aluminum matrix composite at 77 K

Abstract In the present work, the tensile properties and strength-ductility synergy of a B4Cp/6061Al composite prepared by powder metallurgy were investigated at 77 K. The results demonstrated that as the tensile test temperature was decreased from 298 to 77 K, the yield strength, ultimate tensile strength, and strain to failure of the peak-aged 5 wt% B4Cp/6061Al composite increased from ∼340 to ∼380 MPa, ∼389 to∼487 MPa, and ∼11.9% to∼15.6%, respectively; similar trend in the unreinforced 6061Al alloy was observed. The strain hardening capability of the composite exhibited a notable increase at 77 K, suggesting a better resistance to deformation at 77 K. The grains with prestored dislocations and recrystallized grains, which were responsible for the increase in tensile strength and ductility at 77 K, were found in the composite. The matrix strengthening and dislocations generated around the B4C particles resulted in the enhancement of the yield strength of the composite at 77 K. This work provides a reference for the potential application of ceramic particle-reinforced aluminum matrix composites under cryogenic environments.