Cold deformation behavior and the microscopic mechanisms of a L605 centrifugal cast tube

Abstract Cold deformation behavior and microscopic mechanisms of L605 centrifugal cast tubes were studied via room-temperature compression tests. The hardening behavior aligned well with the Hollomon equation, and a high-fidelity cold deformation constitutive relationship was determined using least-squares fitting in Matlab. Increasing cold deformation intensified grain distortion, promoted grain uniformity, and transformed the original columnar grains into elongated strip shapes. During deformation, twin boundaries with an orientation deviation of 60° remained at 1–4 %, whereas low-angle grain boundaries rose markedly, and high-angle grain boundaries declined. At 15 % compression, numerous dislocations were observed within stacking faults, along with SMIT processes. Upon further compression to 30 %, abundant stacking fault intersections emerged, and a geometric model yielded a dislocation motion resistance of 0.784 N m −1 . Subsequent annealing of compressed specimens at 1,100 °C for 30 min unveiled abundant Σ3 (60°⟨111⟩) annealing twin boundaries, demonstrating an inverse relationship between deformation level and annealed grain size. Microscopic M 6 C carbides were trapped at interfaces between annealing twin boundaries and grain boundaries. Additionally, stacking faults arranged in orderly, parallel arrays on annealing twin surfaces, hindering the γ -to-ε phase transition.