Phase transformations in the alloy hastelloy B

The alloy Hastelloy B undergoes phase transformations in the temperature range of 600°–800° C. These phase transformations were studied in some detail by electron microscopy. The essential result of this study was the observed formation of the DO₂₂ structure as an intermediate phase. The DO₂₂ structure is relatively stable in Hastelloy B and its further transformations are easily observable. At 600°C it is transformed to Ni₄ Mo followed by a partial transformation to Ni₃ Mo, whereas at 700°C Ni₃ Mo is formed from DO₂₂ directly.