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GH698合金的基体上分布着不同尺寸的大、小两种Υ′相。其中小Υ′相总是弥散均匀分布的,而大Υ′相的数量和分布均匀程度是受合金元素、结晶组织、热处理制度和变形量等因素的影响。当材料中出现了大Υ′相的不均匀区域(沿变形方向成条带分布),即降低材料的中温塑性、中温持久寿命,显著增加缺口敏感性。这种不均匀性是由于枝晶未破碎、枝干与枝间的成分偏析(Al和Ti),以及材料中Υ′相总量小于20％所致(即合金成分处在中下限)。通过增加Al、Ti、Nb、Mo含量,以增加Υ′相总量和大Υ′相数量,或增大变形量,充分消除枝晶残余,减少成分差异,来消除不均匀性,得到组织均匀、性能稳定的材料。
GH698 alloy matrix distribution of different sizes of large and small two Y ’phase. Among them, the small Y phase is always dispersed and evenly distributed, while the amount and distribution of large Y ’phase are affected by alloying elements, crystal structure, heat treatment system and deformation. When the material appears large Y ’phase non-uniform area (along the deformation direction of the strip distribution), that is, reduce the material’s medium temperature plastic, medium temperature long-life, significantly increased gap sensitivity. This inhomogeneity results from unbroken dendrites, component segregation (Al and Ti) between the branches and branches, and the total amount of the Y ’phase in the material is less than 20% (ie, the alloy composition is at the lower and middle limits). By increasing the Al, Ti, Nb, Mo content, to increase the total amount of Y ’phase and a large number of Y’ phase, or increase the deformation, the full elimination of dendritic residues and reduce differences in composition, to eliminate unevenness, uniform organization , Stable performance of the material.