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通过传统铸造方法和细晶铸造工艺制备一种铸造镍基高温合金的6种不同形态与尺寸的晶粒.结果表明,细晶铸造工艺制备的样品心部为0.5 mm左右的等轴晶,外部为柱状晶.相比传统铸造方法,细晶铸造工艺获得的晶粒较为细小.g’相和碳化物随晶粒尺寸减小而变得细小.室温拉伸性能和550℃下高周疲劳性能随晶粒尺寸降低而提高;在760℃和应力662 MPa条件下,合金的持久性能随晶粒尺寸减小而增加;但在982℃和应力186 MPa条件下,合金的持久性能随之降低.细化晶粒提高了合金的中、低温力学性能,但对其高温力学性能不利.
Six kinds of grains with different shapes and sizes of nickel base superalloy were prepared by the traditional casting method and the fine grain casting technique.The results show that the core of the sample prepared by the fine grain casting process is equiaxed about 0.5 mm, For the columnar crystal.Compared with the traditional casting method, fine grain casting process to obtain the grain is relatively small.g ’phase and the carbide with the grain size decreases and become small.Radial tensile properties at room temperature and 550 ℃ high cycle fatigue properties With the decrease of grain size, the ductility of the alloy increases with the decrease of grain size at 760 ℃ and stress of 662 MPa. However, the ductility of the alloy decreases with the increase of grain size at 982 ℃ and 186 MPa. Grain refinement improves the mechanical properties of the alloy at medium and low temperature, but not at high temperature mechanical properties.