(1. 沈阳理工大学 材料科学与工程学院，沈阳 110159；
2. 中国科学院 金属研究所，沈阳 110016)
摘 要: 研究抽拉速率对DZ483合金微观组织及力学性能的影响。结果表明：随着抽拉速率的提高，合金的一、二次枝晶间距逐渐减小，γ′相尺寸减小，但γ′相的数量增多；共晶组织及枝晶间碳化物的数量增多。碳化物形貌由块状转变成长条状，类型不随抽拉速率的提高而改变。随着抽拉速率的升高，除Cr元素偏析系数在1左右波动外，其余元素的偏析程度都增加，其中W、Mo元素偏析程度明显加重；DZ483合金的持久性能随抽拉速率的提高先升高后降低。不同抽拉速率下，合金断口均呈现出韧性断裂和脆性断裂混合特征，γ′相为合金的主要强化相。随着抽拉速率的提高，一方面，合金中γ′相的数量逐渐增多，尺寸逐渐减小，提高了合金的持久性能；另一方面，由于元素偏析程度加重、碳化物和共晶数量增多及γ′相筏形化规则程度的下降，降低了合金的持久性能。
关键字: DZ483高温合金；定向凝固；抽拉速率；微观组织；持久性能
（1. School of Materials Science and Engineering, Shenyang Ligong University, Shenyang 110159, China;
2. Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China）
Abstract:The effects of withdrawal rate on the microstructure and mechanical properties of directionally solidified DZ483 superalloy were investigated. The results show that, with the withdrawal rate increasing, both the primary and secondary dendrite arm spacing decrease gradually, and the size of γ′ precipitates decreases, but the quantity of γ′ phase increases obviously. The number of eutectic and carbides within the interdendritic region increases. However, the morphology of carbides transforms from blocky into strip-like. Except the Cr element with segregation coefficient of about 1, the segregation of the elements becomes worse with the increase of the withdrawal rate, especially W and Mo. With the increase of the withdrawal rate, the stress rupture life of the alloy increases initially and then decreases. The main fractographic appearance is brittle and tough at different withdrawal rates. With the withdrawal rate increasing, on the one hand, the size of γ′ precipitates decreases, and the quantity increases, which improves the stress-rupture properties. On the other hand, stress-rupture properties of superalloy worsen because of the increase of element segregation, the increase of the number of γ/γ′ eutectic structure and carbides, and the decrease of the irregular morphology of γ′ rafting.
Key words: DZ483 superalloy; directional solidification; withdrawal rate; microstructure; creep properties
