High temperature deformation behavior of a stainless steel fiber-reinforced copper matrix composite

摘要

Hot deformation behavior of stainless steel fiber-reinforced copper matrix composite and the associated microstructural changes have been investigated using compression tests in the temperature range 700-1000 ℃ and strain rate range 0.001-1 s~(-1). The metallographic observations by electron-backscattered diffraction revealed that dynamic recrystallization of stainless steel fibers is the dominant mechanism with inducing ultrafine-grained structures. Deformation bending and cracking through stainless steel fibers and the interfaces were observed to be the hot deformation-induced microstructural features in the concerned composite. The hot deformation behavior was modeled using the dislocation density based Bergstrom's equation which could be applied up to the peak strain. After the peak strain, Kolmogorov-Johnson-Mehl-Avrami equation could successfully predict the hot flow stresses of the studied composite. At different test conditions (temperatures and strain rates), slight variations in Avrami exponent were observed which could be related to transition from cyclic to single peak recrystallization.