TEM and 3D atom probe characterization of DMS4 cast nickel-base superalloy
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Cast nickel-base superalloys possess the required mechanical properties (creep resistance and stress rupture life) at elevated temperatures that make them suitable for turbine blades in aero-engines. The origin of these properties lies in the presence of a simple two phase γ–γ′ microstructure (with cuboidal γ′ particles dispersed in a γ matrix), in spite of the presence of several alloying elements. The cuboidal nature of the γ′ particles arises from an optimal misfit between the two phases, which is a function of the composition of γ and γ′ phases. In addition, several microstructural issues arising out of the partitioning of the alloying elements influences directly the deformation mechanisms in the γ and γ′, and therefore the mechanical properties of the alloy. In this article, we discuss how some of these microstructural issues have been investigated in DMS4, a cast single crystal superalloy, experimentally using TEM and 3DAP techniques.
KeywordsAtom Probe Single Crystal Superalloy Dendritic Core Convergent Beam Electron Diffraction Stress Rupture Life
Transmission electron microscopy
3-dimensional atom probe
Convergent beam electron diffraction
Higher order Laue zone
This research was funded by Defence Research and Development Organization (DRDO), India, under Project DMR-254, ‘Science and Design of Materials at Atomic Scale’. The permission of Director, Defence Metallurgical Research Laboratory (DMRL), Hyderabad, to publish the results is gratefully acknowledged. We acknowledge the contributions of Mr L. Srivardhan (for heat treatment) and Mr Mohan P. Pathak (for 3DAP experiments). The authors are grateful to Professor S. Ranganathan, Indian Institute of Science, and Dr. D. Banerjee, Chief Controller, DRDO for their keen interest and constant encouragement.
- 2.Das N (1999) US Patent 5916384Google Scholar
- 3.Das N, Singh S, Hazari N, Chaterjee D, Praveen VVNSSC (2007) Met Mater Process 19:189Google Scholar
- 4.Miller MK, Smith GDW (1989) Atom probe microanalysis: principles and applications to materials problems. Materials Research Society, PittsburghGoogle Scholar
- 10.Voelkl R, Glatzel U, Feller-Kniepmeier M (1998) Acta Mater 46:439511Google Scholar
- 13.Stadelmann P (2001) Java electron microscopy software (JEMS) Version 1.0724W2001Google Scholar