TY - JOUR
T1 - Influence of cooling rate on the development of multiple generations of γ′ precipitates in a commercial nickel base superalloy
AU - Singh, A. R. P.
AU - Nag, S.
AU - Hwang, J. Y.
AU - Viswanathan, G. B.
AU - Tiley, J.
AU - Srinivasan, R.
AU - Fraser, H. L.
AU - Banerjee, R.
PY - 2011/9
Y1 - 2011/9
N2 - The compositional and microstructural evolution of different generations of γ′ precipitates during the continuous cooling of a commercial nickel base superalloy, Rene88DT, has been characterized by three dimensional atom probe tomography coupled with energy-filtered transmission electron microscopy studies. After solutionizing in the single γ phase field, continuous cooling at a very high rate results in a monomodal size distribution of γ′ precipitates with a high nucleation density and non-equilibrium compositions. In contrast, a relatively slower cooling rate (∼ 24 °C/min) results in a multi-modal size distribution of γ′ precipitates with the larger first generation primary precipitates exhibiting close to equilibrium composition, along with the smaller scale secondary γ′ precipitates, exhibiting non-equilibrium composition (excess of Co and Cr, depleted in Al and Ti). The composition of the γ matrix near these precipitates also exhibits similar trends with the composition being closer to equilibrium near the primary precipitates as compared to the secondary precipitates.
AB - The compositional and microstructural evolution of different generations of γ′ precipitates during the continuous cooling of a commercial nickel base superalloy, Rene88DT, has been characterized by three dimensional atom probe tomography coupled with energy-filtered transmission electron microscopy studies. After solutionizing in the single γ phase field, continuous cooling at a very high rate results in a monomodal size distribution of γ′ precipitates with a high nucleation density and non-equilibrium compositions. In contrast, a relatively slower cooling rate (∼ 24 °C/min) results in a multi-modal size distribution of γ′ precipitates with the larger first generation primary precipitates exhibiting close to equilibrium composition, along with the smaller scale secondary γ′ precipitates, exhibiting non-equilibrium composition (excess of Co and Cr, depleted in Al and Ti). The composition of the γ matrix near these precipitates also exhibits similar trends with the composition being closer to equilibrium near the primary precipitates as compared to the secondary precipitates.
KW - Atom probe tomography
KW - Energy-filtered transmission electron microscopy
KW - Gamma prime
KW - Nickel base superalloy
UR - http://www.scopus.com/inward/record.url?scp=79960575262&partnerID=8YFLogxK
U2 - 10.1016/j.matchar.2011.06.002
DO - 10.1016/j.matchar.2011.06.002
M3 - Article
AN - SCOPUS:79960575262
SN - 1044-5803
VL - 62
SP - 878
EP - 886
JO - Materials Characterization
JF - Materials Characterization
IS - 9
ER -