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利用多功能雾化沉积装置,制备了 Ni3Al-Mo 高温合金。拉伸性能测试表明:喷射沉积 Ni3Al-Mo 合金的屈服强度有明显的“R”特性,即喷射沉积合金的屈服强度随着温度的增加而增加,在 760 ℃时达到最大值;随着温度的继续增加,屈服强度会逐渐降低。利用 TEM 对位错结构分析,阐明了合金屈服强度与微观结构之间的关系。研究结果表明,试验合金所具有的屈服强度随温度的变化规律主要是由不同温度下γ′及γ相内的位错缠结状况、位错对的形态及数量和六面体滑移系的开动程度决定的。裂纹的 TEM 分析表明,随着变形应力的增加,裂纹在晶界部位产生,然后迅速扩展,而且在不同的晶面内存在一些不同的滑移带。喷射沉积合金在室温、中温及高温下裂纹严格沿八面体滑移系(111)面开裂。
Ni3Al-Mo superalloy was prepared by multifunctional atomization deposition equipment. Tensile tests show that the yield strength of spray-deposited Ni3Al-Mo alloy has obvious “R” character, that is, the yield strength of spray deposited alloy increases with the increase of temperature and reaches the maximum at 760 ℃. With the increase of Temperature continues to increase, yield strength will be gradually reduced. Using TEM analysis of the dislocation structure, the relationship between the yield strength and the microstructure of the alloy was clarified. The results show that the variation of yield strength with temperature of the test alloy is mainly caused by the dislocation entanglement in the γ ’and γ phases at different temperatures, the shape and number of dislocation pairs and the degree of activation of the hexahedral slip system decided. The crack TEM analysis shows that with the increase of the deformation stress, the crack is generated in the grain boundary and then rapidly spread, and there are some different slip bands in different crystal planes. Spray deposited alloy cracked strictly along the (111) octahedral slip system at room temperature, medium temperature and high temperature.