Proceedings of the 43rd International Field Emission Symposium
J. Phys. IV France 06 (1996) C5-259-C5-264
An Atom Probe Field Ion Microscope Study of Model Ni-Al Superalloys Containing BeR.C. Thomson1, K.F. Russell2 and M.K. Miller2
1 Institute for Polymer Technology and Materials Engineering, Loughborough University, Loughborough, Leicestershire, LE11 3TU, U.K.
2 Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6376, U.S.A.
Atom probe field ion microscopy and transmission electron microscopy have been used to characterise the phases present, and their compositions, in four model Ni-Al superalloys containing Be. In agreement with the limited information available on phase stability within the ternary Ni-Al-Be system, atom probe results indicated that these alloys were in the three phase, γ-Ni, γ-Ni3Al and β-NiBe, region of the ternary diagram. Beryllium was found to substitute on the 'Al' sites within the γ, consistent with previous results from Be-doped NiAl. The experimental results have shown that the Be additions have resulted in the precipitation of phases enriched in Be within the γ phase. The morphology of the phases enriched in Be ranged from monatomically thick plates to lenticular precipitates. Hardness measurements indicate significant hardening resulting from the addition of Be to model Ni-Al alloys.
© EDP Sciences 1996