【摘要】 为了研究某型号镍基定向凝固高温合金在高温时效过程中组织及性能的演变规律,利用扫描电镜、纳米压痕仪、疲劳试验机等测试方法对该型号高温合金高温时效前后微观组织及力学性能进行测试。结果表明:该型号高温合金经980℃长时高温时效后,γ’相显著粗化,但其基本形态仍呈立方态分布;共晶γ’相的硬度和弹性模量基本保持不变,而枝晶干的硬度及弹性模量均有所下降,对应宏观力学性能则表现为拉伸强度及980℃×250 MPa持久寿命有所下降。此外,高温时效前后,无论是平均弹性模量还是平均硬度,横向都比纵向<001>方向的大。这种共晶γ’相和枝晶干的力学性能所具有的方向性对于研究镍基定向凝固高温合金的各向异性有着重要的意义。更多还原

【Abstract】 To study the evolution law of microstructures and mechanical properties of directionally solidified nickel-base superalloy under high temperature aging,the microstructure and mechanical properties of directionally solidified nickel-base superalloy before and after high temperature aging were tested by the means of scanning electron microscope( SEM),nano-indenter,fatigue testing machine. The results indicate that after long-term aged at 980 ℃,the size of γ’ phase increases significantly,but the basic morphology of γ’ phase is basically cubic shape,the changes of hardness and modulus of the eutectic γ’ phase are not apparent,while the hardness and modulus of the dendrite arm of γ’ phase is decreased,and the tensile strength and creep rupture life under 980 ℃/250 MPa are decreased. In addition,both average elasticity modulus and hardness,no matter aging or not,in the vertical direction of the columnar crystal are higher than those in the parallel direction of < 001 >. It is of great significant to study the anisotropy of directional solidification nickel-base superalloy for the direction of the mechanical properties of the eutectic γ’ phase and dendrite arm γ’ phase.更多还原