Phase Transformations in the Oxygen-Enriched Case Layer of Beta Titanium Alloys Formed During Oxidation (Preprint).

摘要

The formation of an oxide layer along together with alpha precipitation in the subsurface oxygenenriched zone, during the oxidation of a Beta-Ti alloy, has been investigated using SEM, (S)TEM, and nanoindentation. Just below the nanocrystalline oxide layer, a two-phase mixture consisting of nanoscale equiaxed alpha grains and rutile grains is formed. Further below, the morphology of the alpha precipitates transitions to more lath-like with their size-scale, nucleation density, and the volume fraction of Beta progressively changing with increasing depth.