Influence of Cr addition on microstructure of a 5% Re-containing single crystal nickel-based superalloy

来源期刊:中国有色金属学报(英文版)2011年第5期

论文作者:谭喜鹏 刘金来 金涛 孙晓峰 胡壮麒

文章页码:1004 - 1008

关键词:Cr;Re;单晶高温合金;错配度;微观组织

Key words:Cr; Re; single crystal superalloy; misfit; microstructure

摘    要:

在一种含5%Re(质量分数)和3%Cr的镍基单晶高温合金基础上,研究再添加Cr后合金组织的变化。实验结果表明:随着Cr含量的增加,合金铸态组织中元素偏析加重,共晶体积分数增加,固相线和液相线温度显著降低。此外,完全热处理态组织中γ′尺寸和体积分数都减小。X射线衍射分析结果表明,Cr的添加使γ/γ′点阵错配度变得更负。从能量色散谱仪的结果可知,Cr主要分布在γ基体中,并且随着Cr含量的增加,更多的γ基体形成元素(如Re和W等)进入γ基体中,但Cr在γ/γ′中的分配比却减小。

Abstract:

Based on a 5% (mass fraction) Re-containing single crystal nickel-based superalloy with 3% (mass fraction) Cr, the microstructural variation with Cr addition was investigated. The experimental results show that segregation of alloying elements was enhanced in as-cast microstructure with Cr addition; and the volume fraction of eutectic is increased. However, the solidus and liquidus temperatures are remarkably reduced. With the increase of Cr content, the average γ¢ size and volume fraction are decreased in the fully heat treated microstructure. X-ray diffraction results indicate that γ/γ¢ lattice misfit becomes more negative. According to the energy dispersive spectroscopy (EDS) results, Cr is mainly distributed in the γ matrix; and more γ-forming elements, such as Re and W, enter the γ matrix, while the γ/γ¢ partition ratio of Cr is inversely decreased.

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