Microstructural development in dispersion strengthened NiAl produced by mechanical alloying and secondary recrystallization
- Max-Planck-Inst. fuer Metallforschung and Inst. fuer Metallkunde der Universitaet, Stuttgart (Germany)
In order to improve the creep strength of NiAl, the authors have developed oxide-dispersion strengthened (ODS) NiAl alloys through a powder metallurgical processing route involving Mechanical Alloying (MA) and secondary recrystallization. The powders and the consolidated material are analyzed by means of TEM, quantitative metallography and X-ray diffraction. Particular attention is paid to achieving, by thermomechanical processing, a favorable microstructure in terms of creep strength, i.e., a large grain size and finely distributed dispersoids. It is found that undesirable coarsening of dispersoids during recrystallization can be reduced by encouraging abnormal grain growth (secondary recrystallization) through predeformation. The connection between grain growth and dispersoid coarsening is analyzed quantitatively. Overall, it is demonstrated that the conflicting requirements of large grains and relatively fine dispersoids can be satisfied by well-defined processing steps.
- OSTI ID:
- 445335
- Journal Information:
- Acta Materialia, Journal Name: Acta Materialia Journal Issue: 1 Vol. 45; ISSN 1359-6454; ISSN ACMAFD
- Country of Publication:
- United States
- Language:
- English
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