Effect of cryogenic rolling and intermediate aging on mechanical reinforcement of the Cu-Fe-Nb composites

The effect of cryogenic rolling and intermediate aging on the microstructure and properties of the Cu-10Fe-1Nb composites were investigated. After aging for 1800 min, the microhardness, tensile strength and elongation of the Cu-10Fe-1Nb samples reached 158 HV, 623 MPa and 22%, respectively. The microstructure results showed that the fibrous Fe-rich phases and the matrix of the Cu-10Fe-1Nb samples were refined significantly after cryogenic rolling. It could be attributed to the increasing shear strain between the Fe-rich phases and matrix with dislocation density of the matrix, which inhibited the dynamic recovery recrystallization of the matrix. The intermediate aging promoted the dissolved Fe to precipitate obviously, and these precipitates effectively impeded the recrystallization of the matrix during the subsequent aging process. The improvement of mechanical properties was mainly attributed to the Orowan strengthening, refinement strengthening and work hardening resulted from the numerous precipitates, fine grains and high-density dislocation in the matrix, respectively.