Investigation on the σ-phase-related equilibria in Cr-Mn-Co system

•The phase equilibria of the Cr-Mn-Co ternary system were investigated.•Isothermal sections at 900, 1050, 1150, and 1200 °C were determined.•The σ phase forms a continuous solid solution from Cr-Co side to Cr-Mn side at all temperatures investigated.•The solubility of Co in the (Cr) phase decreases with the increasing Mn content at all temperatures investigated.