(1. 沈陽理工大學(xué) 材料科學(xué)與工程學(xué)院，沈陽 110159；
2. 中國科學(xué)院 金屬研究所，沈陽 110016)
摘 要: 研究抽拉速率對DZ483合金微觀組織及力學(xué)性能的影響。結(jié)果表明：隨著抽拉速率的提高，合金的一、二次枝晶間距逐漸減小，γ′相尺寸減小，但γ′相的數(shù)量增多；共晶組織及枝晶間碳化物的數(shù)量增多。碳化物形貌由塊狀轉(zhuǎn)變成長條狀，類型不隨抽拉速率的提高而改變。隨著抽拉速率的升高，除Cr元素偏析系數(shù)在1左右波動外，其余元素的偏析程度都增加，其中W、Mo元素偏析程度明顯加重；DZ483合金的持久性能隨抽拉速率的提高先升高后降低。不同抽拉速率下，合金斷口均呈現(xiàn)出韌性斷裂和脆性斷裂混合特征，γ′相為合金的主要強化相。隨著抽拉速率的提高，一方面，合金中γ′相的數(shù)量逐漸增多，尺寸逐漸減小，提高了合金的持久性能；另一方面，由于元素偏析程度加重、碳化物和共晶數(shù)量增多及γ′相筏形化規(guī)則程度的下降，降低了合金的持久性能。
關(guān)鍵字: DZ483高溫合金；定向凝固；抽拉速率；微觀組織；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
