Tuning microstructures and improving oxidation resistance of Nb-Si based alloys via electron beam surface melting

The bottleneck for the application of Nb-Si based alloys as high-temperature alloys is their poor oxidation resistance. Here we present an approach to tune the microstructures and enhance the oxidation resistance via electron beam surface melting (EBSM) treatment. Significant microstructural refinement, higher volume fraction of silicides and controlled phase regime are achieved by EBSM. The oxidation tests at 1250 °C demonstrate a substantially improved oxidation resistance of the EBSM-processed alloy, with a thinner, less wrinkled oxide scale. A continuous silica layer within the oxide scale is produced on the remelted surface. The oxidation response to tunable microstructures is discussed.