Carnegie Mellon University | Department of Chemical Engineering

Alloy Oxidation Resistance Across Multicomponent Composition Space

Matthew Payne, James Miller, Andrew Gellman

The oxidation of multicomponent metal alloys, AxByC1-x-y, is a kinetically complex process that is not fully understood for many systems. As a result the design of oxidation-resistant alloys typically requires an empirical determination of the optimal composition. The comprehensiveness with which prospective alloy composition spaces, (x,y), can be screened has conventionally been limited by the time required to prepare and test large numbers of single-composition alloy samples. We have pioneered the development and use of high-throughput methods to study the composition dependence of alloy oxidation using composition spread alloy films (CSAFs), i.e. alloy thin films containing lateral gradients in composition. By analyzing different locations across the surface of a single, oxidized CSAF with spatially resolved characterization techniques (e.g. energy-dispersive X-ray spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy), we can screen oxidation behavior across a continuous range of alloy compositions, x = 0 → 1 and y = 0 → 1-x. We have used this concept to identify continuous boundaries dividing regions of composition space exhibiting different degrees of oxidation resistance for the ternary AlxFeyNi1-x-y alloy system. Our current work applies similar approaches to study oxidation resistance in quaternary Al-Fe-Ni-Cr steels used in many industrially important alloys. Our high-throughput studies reveal in unprecedented detail how changes in composition influence oxidation resistance, and they offer important fundamental insights into the mechanisms of multicomponent-alloy oxidation.

Figure 1. An ~100 nm-thick AlxFeyNi1-x-y CSAF (x = 0 → 1, y = 0 → 1-x) which was oxidized for 4 h in dry air at 700 K. The composition of the CSAF changes continuously across its surface, as indicated by the overlaid grid. The color variations across the surface develop as the result of oxidation and can be used to identify four regions with qualitatively unique oxide structure. Areas which form a continuous Al2O3 layer are most resistant to oxidation.

Related Publications

  1. M.A. Payne, J.B. Miller, A.J. Gellman, "High-throughput characterization of the effects of H2O vapour on early oxidation across AlxFeyNi1-x-y composition space" Corros. Sci. ; 2016. View paper
  2. M.A. Payne, J.B. Miller, A.J. Gellman, "High-throughput characterization of early oxidation across AlxFeyNi1-x-y composition space" Corros. Sci. ; 2015 , 91, 46-57. View paper