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Microstructure, chemistry and mechanical properties of Ni-based superalloy Rene N4 under irradiation at room temperature.

Authors :
Sun, C.
Kirk, M.
Li, M.
Hattar, K.
Wang, Y.
Anderoglu, O.
Valdez, J.
Uberuaga, B.P.
Dickerson, R.
Maloy, S.A.
Source :
Acta Materialia. Aug2015, Vol. 95, p357-365. 9p.
Publication Year :
2015

Abstract

Nickel superalloys with cubic L1 2 structured γ′ (Ni 3 (Al, Ti)) precipitates exhibit high strength at high temperatures and excellent corrosion resistance when exposed to water. Unlike prior studies on irradiation damage of other Ni-based superalloys, our study on Rene N4 involves much larger γ′ precipitates, ∼450 nm in size, a size regime where the irradiation-induced disordering and dissolution kinetics and the corresponding mechanical property evolution are unknown. We report that under heavy ion irradiation at room temperature, the submicron-sized γ′ precipitates were fully disordered at ∼0.3 dpa and only later partially dissolved after 75 dpa irradiation. Nanoindentation experiments indicate that the mechanical properties of the alloy change significantly, with a dramatic decrease in hardness, with irradiation dose. Three contributions to the change in hardness were examined: defect clusters, disordering and dissolution. The generation of defect clusters in the matrix and precipitates slightly increased the indentation hardness, while disordering of the submicron-sized γ′ precipitates resulted in a dramatic decrease in the total hardness, which decreased further during the early stages of the intermixing between γ′ precipitates and matrix (<18 dpa). Controlling the long-range-ordering and chemical intermixing can be used to tailor the mechanical properties of Ni-based superalloys under irradiation. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
13596454
Volume :
95
Database :
Academic Search Index
Journal :
Acta Materialia
Publication Type :
Academic Journal
Accession number :
103656388
Full Text :
https://doi.org/10.1016/j.actamat.2015.04.061