μ Phase in a Nickel Base Directionally Solidified Alloy

Abstract

Scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD) were employed to study the μ phase in a directionally solidified experimental nickel base alloy. It was observed that the μ phase distribute at interdendritic area and precipitate mainly from the γ′ phase in this experimental alloy. Orientation relationship between the γ′ and the μ phase was found as (111)_γ′||(0001)_μ and ⟨\\bar110⟩_γ′||⟨11\\bar20⟩_μ. Detrimental effect of the μ phase on oxidation resistance of the alloys was also found.