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浇注了两种不同尺寸的镍基单晶高温合金铸件试样,研究了试样尺寸对显微组织的影响,利用扫描电镜分析了合金的断口形貌和断裂机制。结果表明,浇注试样尺寸增大,合金的枝晶间距和热处理后γ′相的尺寸增大。合金在760、980℃下的拉伸性能以及980℃和250MPa条件下的持久性能均有不同程度的降低。合金760℃的拉伸断裂为类解理断裂,980℃的拉伸断裂以及980℃和250MPa条件下的应力断裂都为韧窝断裂。
Casting two different sizes of nickel-base single crystal superalloy castings samples, the impact of sample size on the microstructure was studied by scanning electron microscopy fracture morphology and fracture mechanism. The results show that the size of the cast sample increases, the dendrite spacing of the alloy and the size of γ ’phase increase after heat treatment. Tensile properties of the alloy at 760,980 ℃ and the durability at 980 ℃ and 250MPa all have different degrees of reduction. Tensile fracture at 760 ℃ is cleavage-like fracture, fracture at 980 ℃ and stress fracture at 980 ℃ and 250MPa.