Production of chromium base alloys by ball milling in hydrogen iodide

The effects of processing variables on the tensile properties and ductile-to-brittle transition temperature (DBTT) of Cr+4 vol pct ThO₂ alloys and of pure Cr produced by ball milling in hydrogen iodide were investigated. Hot rolled Cr+ThO₂ was stronger than either hot pressed Cr+ThO₂ or pure Cr at temperatures up to 1540°C. Hot pressed Cr+ThO₂ had a DBTT of 500°C as compared with ?8°, to 24°C for the hot rolled Cr+ThO₂ and with 140°C for pure Cr. It is postulated that the dispersoid in the hot rolled alloys lowers the DBTT by inhibiting recovery and recrystallization of the strained structure.