Phase transformation from body-centred cubic to face-centred cubic in oxide dispersion strengthened (ODS) Molybdenum-Rhenium alloy

Molybdenum (Mo) is a refractory metal that maintains a body-centred cubic (bcc) structure at all temperatures before melting. Thus, metastable face-centred cubic (fcc) Mo that can be reserved at ambient temperatures had rarely been reported in the literature. In this study, an oxide dispersion strengthened (ODS) molybdenum-rhenium (Mo-Re) alloy containing fcc Mo was successfully prepared via high-energy milling and spark plasma sintering (SPS). This alloy exhibits excellent compressive properties at room temperature. The mechanism regarding the bcc-to-fcc phase transformation was analyzed, and two specific orientation relationships—Kurdjumov-Sachs and Nishiyama-Wasserman—between the bcc Mo-Re matrix and fcc Mo were confirmed. Additionally, the role of oxides in affecting the phase transformation was discussed.