高强耐腐蚀Ti80合金的热变形行为及热轧板材的组织性能研究

Study on Hot Deformation Behavior of High-strength and Corrosion-resistant Ti80 Alloy and Microstructure and Properties of Hot Rolled Sheet

摘要:

通过热模拟实验研究Ti80合金热变形行为及组织演化规律，考察该合金的应力-应变曲线、加工硬化规律并建立该合金的热加工图。在此基础上，进行不同热轧工艺下的Ti80合金板材制备，研究其微观组织变化及对力学性能的影响，探索Ti80合金具有最优力学性能的工艺条件。结果表明：Ti80合金峰值应力和加工硬化率随着变形温度的升高以及变形速率的降低而减小，属于变形温度和应变速率敏感型合金。通过热加工图计算分析，温度为800℃~920℃、920℃～1050℃，应变速率为0.01s-1～0.1s-1范围内为最佳的稳定变形区。随着变形温度的升高，其微观组织经历由等轴组织、双态组织到层片组织的变化。同时，随着应变速率的升高，存在β转变组织形态的变化。对比分析Ti80合金不同热轧条件下的力学性能，初轧温度1060℃、终轧温度950℃时，显示为网篮组织+块状α相的混合组织形态，此时具有最优的强度和塑性性能，抗拉强度为881Mpa，而延伸率为11.27%，展现为韧性断裂。

Abstract:

Research the hot deformation behavior and microstructure evolution of Ti80 alloy through hot compression tests, investigate the stress-strain curve and work hardening law of the alloy, and establish the hot processing map of the alloy. Then, Ti80 alloy sheets under different hot rolling processes were prepared, and the microstructure changes and their effects on mechanical properties were studied. Explore the process conditions for Ti80 alloy with optimal mechanical properties. The result shows: The peak stress and work hardening rate of Ti80 alloy decrease with the increase of deformation temperature and decrease of deformation rate. there exist strain rate and deformation temperature sensitivity in this alloy. According to the calculation and analysis of the hot processing map, the temperature range of 800℃~920℃, 920℃～1050℃, and strain rate of 0.01s-1～0.1s-1 is the best stable deformation zone.As the deformation temperature increases, its microstructure undergoes a change from equiaxed grain structure, duplex structure to fully lamellar structure. At the same time, as the strain rate increases, there is a change in the morphology of the β transition matrix. The mechanical properties of Ti80 alloy under different hot rolling conditions are compared and analyzed. When the initial rolling temperature is 1060℃ and the final rolling temperature is 950℃, it shows a mixed microstructure of basketweave microstructure + block α phase, which has the best tensile strength and plasticity performance, tensile strength is 881Mpa, and elongation is 11.27%, showing ductile fracture.