温度对 Nb521 铌合金包套轧制组织与性能的影响

In this paper, Nb521 niobium alloy was rolled by reduction rate of 45% in the temperature range of 1050−1250 ℃ using the pack rolling process. The effects of rolling temperature on microstructure characteristics, dynamic recrystallization behavior, texture evolution and mechanical properties were systematically analyzed. The results show that rolling temperature significantly influences the grain orientation distribution. As the rolling temperature increases from 1050 ℃ to 1250 ℃, the grain orientation transforms from ND// 〈001〉〈/ 111〉double-pole distribution to ND// 〈111〉single-pole distribution. In addition, the high dislocation density is maintained in the rolled sheets at different temperatures, and the degree of dynamic recrystallization is low. The discontinuous dynamic recrystallization and continuous dynamic recrystallization mechanisms coexist, but the dynamic recovery still dominates. The transformation of {111}〈112〉γ fiber texture to {111}〈110〉γ/α fiber texture with increasing temperature contributes significantly to the enhanced plastic deformation ability of the alloy. The sheet rolled at 1050 ℃ exhibits superior strength, with yield and ultimate tensile strengths of 629.7 MPa and 738.4 MPa. In contrast, the sheet rolled at 1250 ℃ achieves an optimal elongation of 18.4%. Finally, The fracture analysis confirms a mixed ductile-brittle fracture mode for all rolled specimens.