Authors
Nithin Baler, Prafull Pandey, Dhanalakshmi Palanisamy, Surendra Kumar Makineni, Gandham Phanikumar, Kamanio Chattopadhyay
Publication date
2020/5/1
Journal
Materialia
Volume
10
Pages
100632
Publisher
Elsevier
Description
The effect of replacement of molybdenum with small amount of tungsten on the stability of cobalt based superalloys of Co–Ni–Mo–Al–Ta–Ti class has been presented. A small addition of tungsten (W) in Co–30Ni–(5-x)Mo–10Al–2Ta–2Ti–2W alloys stabilizes the cuboidal morphology of precipitates and increases the γ′ volume fraction. A 2 at% addition of W causes an increase of 60 °C in solvus temperature of the base superalloy to reach a value of 1130 °C with a slight increase of mass density to 8.79 g/cc. Beside partitioning into γ′, W also shifts the partitioning preference of Mo from the γ′ phase in 0W alloy to that of equal partitioning in both γ and γ’ phases in 2W alloy. An interfacial confinement of Mo atoms could be observed at the γ/γ′ interfaces that reduces interface energy leading to enhanced microstructural stability. The experimentally determined temporal evolution of average precipitate size in the 2W …
Scholar articles
N Baler, P Pandey, D Palanisamy, SK Makineni… - Materialia, 2020