Study of the Microstructure and Oxidation Behavior of Chromium Base Alloys Strengthened by NiAl Precipitates

Laurent Royer; Stéphane Mathieu; Christophe Liebaut; Pierre Steinmetz

doi:10.4028/www.scientific.net/MSF.595-598.117

Paper Titles

Influence of Micro-Structure on Oxidation Behavior of a Ni-Based Superalloy at 1000°C
p.87

Short-Time Oxidation of a NiAl(Zr) Bond Coat Thermochemically Deposited on a Nickel-Based Superalloy
p.95

Oxide Spallation in Beta-NiAl Coated Systems under Mechanicalloading
p.101

Creep Deformation / Oxidation Behavior of Re-Cr-Ni Diffusion Barrier Coated Hastelloy-X at 970°C in Air
p.107

Study of the Microstructure and Oxidation Behavior of Chromium Base Alloys Strengthened by NiAl Precipitates
p.117

A Novel Duplex Re-NiW Based Diffusion Barrier on a Nickel-Base Superalloy for TBC Systems
p.127

Formation of Pt-Modified γ’-Ni₃Al and Re-Based σ-Alloy Coating System and Cyclic Oxidation Behavior of Coated Superalloy
p.135

Preliminary Results of the Isothermal Oxidation Study of Pt-Al-NiCoCrAlYTa Multi-Layered Coatings Prepared by Sparks Plasma Sintering (SPS)
p.143

A Prototype Software Tool for Life Time Assessment of Thermal Barrier Coating Systems
p.151

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Study of the Microstructure and Oxidation Behavior of Chromium Base Alloys Strengthened by NiAl Precipitates

Abstract:

In this study, chromium based alloys containing a hardening NiAl phase are investigated from 1100°C to 1300°C in air. The influence of the NiAl content and of the Al/Ni ratio on microstructure modification and on oxidation behaviour are characterized by metallography and thermogravimetry. Increasing the Al/Ni ratio leads to a higher Al content in the chromium solid solution but does not modify the amount of primary NiAl. At high temperature, and for NiAl content exceeding 16 at%, a duplex oxide layer forms at the surface of the alloys exposed in air, alumina in the inner part, and chromia in the outer part. The oxidation behavior is discussed according to oxidation profile and to the thermodynamic predominance diagram of the involved species.