Effect of Nb content on mechanical reinforcement of the Cu-10Fe composites

Abstract

The Cu-10Fe-based composites with different Nb content were fabricated by vacuum mold casting. The effect of Nb content on the solidification behavior and microstructure was investigated systematically and the optimal composition was determined as Cu-10Fe-1.0 Nb (wt%). The as-cast samples were rolled by 90% reduction at room and then aged at 250 ℃ for different time. The properties results showed that, after aging for 1800 min, microhardness, tensile strength and elongation of the Cu-10Fe-1.0 Nb samples reached 145 HV, 553 MPa and 21.5%, respectively. The microstructure results showed that the primary Fe-rich phases in the Cu-10Fe-1.0 Nb samples were significantly refined due to the heterogeneous nucleation induced by Fe2Nb phases, and then led to the refinement of the matrix. The enhanced mechanical properties could be attributed to the Orowan strengthening, refinement strengthening and work hardening resulted from the numerous submicron-/nano-sized Fe particles, fine sub-grains and high-density dislocation in the matrix formed during thermo-mechanical treatment.