Abstract Scope |
Refractory multi-principal element alloys (RMPEAs) are considered a promising class of materials for extreme environment applications due to their excellent high temperature properties. Refractory alloys, however, are widely known to be susceptible to environmental degradation at elevated temperatures. Thus, oxidation resistance is a key consideration when investigating RMPEAs. The vast majority of extant literature regarding the oxidation of RMPEAs has focused on high temperatures, typically 1000ºC or higher, but these approaches do not directly provide information regarding the initial stages of oxidation and its progression. To this end, in air annealing at 200-400ºC was conducted on MoNbTaW films. XRD, SEM, TEM, and XPS were used to quantify solute ingress and phases present. Comparison was then made to pure W thin films under the same conditions. Through understanding of the initial stages of oxidation, the alloy chemistry can be tailored to improve phase stability in extreme environments. |