Cast nickel-based superalloys INC713 LC, B1914 and MAR-M247 are widely used for high temperature components in the aerospace, automotive and power industries due to their good castability, high level of strength properties at high temperature and hot corrosion resistance. The present study is focused on the mutual comparison of the creep properties of the above-mentioned superalloys, their creep and fracture behaviour and the identification of creep deformation mechanism(s). Standard constant load uniaxial creep tests were carried out up to the rupture at applied stress ranging from 150 to 700 MPa and temperatures of 800–1000 °C. The experimentally determined values of the stress exponent of the minimum creep rate, n, were rationalized by considering the existence of the threshold stress, σ₀. The corrected values of the stress exponent correspond to the power-law creep regime and suggest dislocation climb and glide as dominating creep deformation mechanisms. Fractographic observations clearly indicate that the creep fracture is a brittle mostly mixed transgranular and intergranular mode, resulting in relatively low values of fracture strain. Determined main creep parameters show that the superalloy MAR-M247 exhibits the best creep properties, followed by B1914 and then the superalloy INC713 LC. However, that each of the investigated superalloys can be successfully used for high temperature components fulfils the required service loading conditions.

中文翻译：

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铸造镍基高温合金INC 713 LC，B1914和MAR-M247的高温蠕变行为

铸造镍基高温合金INC713 LC，B1914和MAR-M247具有良好的可铸造性，高温下的高强度特性和耐热腐蚀性能，因此广泛用于航空航天，汽车和电力工业中的高温部件。本研究的重点是上述超级合金的蠕变性能，蠕变和断裂行为的相互比较以及蠕变变形机理的识别。在150至700 MPa的施加应力和800-1000°C的温度下，进行了直至断裂时的标准恒定载荷单轴蠕变测试。实验确定的最小蠕变速率的应力指数值，Ñ，通过考虑阈值应力的存在被合理化，σ ₀。应力指数的校正值与幂律蠕变状态相对应，表明位错爬升和滑移是主要的蠕变变形机制。断层扫描观察清楚地表明，蠕变断裂是脆性的，主要是混合的跨晶和晶间模式，导致相对较低的断裂应变值。确定的主要蠕变参数表明，超级合金MAR-M247具有最佳的蠕变性能，其次是B1914，然后是超级合金INC713 LC。但是，每种被研究的高温合金都可以成功地用于高温部件，从而满足所需的使用负荷条件。