协同获得两类特殊晶界对Inconel 617合金高温氧化行为的影响

The co-effect of two kinds of special grain boundaries on high temperature oxidation behavior of Inconel 617 alloy

摘要:

本文以Inconel 617合金为研究对象,通过形变控冷处理工艺协同引入两类特殊晶界,分析晶界特征对合金高温氧化性能的影响。结果表明：采用形变控冷处理,可将Inconel 617合金中的Σ3_ⁿ晶界比例提升至70%以上；同时,获得平均振幅为0.83μm,平均波长为15.98μm的锯齿晶界,锯齿晶界形成与晶界析出Mo₆C和Cr₂₃C₆型碳化物钉扎晶界有关。协同获得两类特殊晶界可有效改善合金的抗高温氧化性能,表现为显著降低基体表面Cr₂O₃氧化层厚度以及基体中Al₂O₃沿晶界的扩散深度；这主要是由于Σ3_ⁿ晶界、锯齿晶界以及非连续的平直随机晶界网络可有效抑制Cr和O元素沿晶界扩散。

Abstract:

The effect of microstructure with high fraction of Σ3_ⁿ boundaries and serrated grain boundaries (SGBs) on high temperature oxidation of Inconel 617 is studied. After deformation then slowing cooling treatment, the fraction of Σ3_ⁿ boundaries can be increased to over 70% also simultaneously changing some of the rest random grain boundaries (RGBs) into SGBs with the average amplitude of 0.83μm and the average wavelength of 15.98μm. The formation of SGB is associated with the precipitation of Mo₆C和Cr₂₃C₆ carbides at RGB. The microstructure with two types of special grain boundaries (GBs) can effectively improve the high temperature oxidation resistance, which is reflected in significantly reducing the thickness of Cr₂O₃ surface oxide layer and the diffusion depth of Al₂O₃ along the GB. This is attributed to that Σ3_ⁿ boundaries, SGBs and unconnected straight RGB network can effectively retard the diffusion of Cr and O elements along the GB.