时效强化X-750镍基合金高温弹塑性特征及本构模型计算研究

Research on High-temperature Elastic-plastic Characteristics and Constitutive Model Calculation of Aging Strengthened X-750 Nickel-based Alloy

研究了时效强化状态0Cr15Ni70Ti3AlNb（X-750）镍基合金材料在300~600℃内的高温弹塑性特征。采用Johnson-Cook本构关系式模型对该合金的高温力学性能进行了分析。结果表明：经过两步法时效强化处理后的X-750镍基合金材料在0.006~0.3 min（-1）的不同应变速率条件下,其高温抗拉强度随测试温度的升高从约1113 MPa显著降低至825 MPa。然而高温屈服强度的变化幅度仅为约50 MPa,且受测试温度的影响不规律,导致热软化因子m的拟合结果不规则。另外,应变硬化因子B、加工硬化指数n和应变速率硬化因子C在内的其他参数的拟合一致性显著优于热软化因子m,这表明热变形对X-750合金高温强度的影响较为规律。

The high-temperature elastic-plastic characteristics of aging-strengthened 0Cr15Ni70Ti3AlNb（X-750）nickel-based alloy within the range of 300℃to 600℃were researched.The high-temperature mechanical properties of the alloy were analyzed based on Johnson-Cook constitutive model.The results show that with test temperature increasing,the tensile strength with strain rate changing from 0.006 min^-1to 0.3 min^-1of two steps aging-strengthened X-750 nickel-based alloy obviously decreases from approximately 1113 MPa to 825 MPa.However,the variation interval of the high temperature yield strehgth is only 50 MPa,and the effect of test temperatures on the yield strength is irregular.This phenomenon leads to the fitting results of thermal-soften factor m irregular.Besides,the fitting consistency of the other parameters,including strain-harden factor B,work-harden index n and strain rate-harden factor C is far better than that of thermal-soften factor m,which indicates that the influence of hot-deformation on the high-temperature strength of X-750 alloy is more regular.