Mo Effect on the Microstructure in Co-Al-W-Based Superalloys
The as-cast and heat-treated microstructure has been investigated in Co-Al-W-based superalloys with additions of 2 and 4 at.% Mo. The results revealed that Mo promoted the formation of (μ+γ) eutectic structure in the as-cast alloys and μ-phase precipitation after solution treatment. In addition, after aging treatment at 900oC, an extensive network of DO19 precipitates was observed, besides the γ+γ′ primary phases and the μ phase inherited from the as-cast and solution-treated conditions. Meanwhile, a solid-state transformation from the μ phase to the DO19 phase occurred; and long-term aging enhanced this transformation. In addition, high levels of Mo promoted the DO19-phase precipitation.
Jian-Feng Nie and Allan Morton
F. Xue et al., "Mo Effect on the Microstructure in Co-Al-W-Based Superalloys", Materials Science Forum, Vols. 654-656, pp. 420-423, 2010