Research of phase transformation on Fe–8.7Al–28.3Mn–1C–5.5Cr alloy

This investigation elucidates the phase transformations of the Fe–8.7Al–28.3Mn–1C–5.5Cr alloy using optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy-dispersive X-ray spectrometer (EDS). As the alloy was solution heat treated and then quenched, a (γ + Cr7C3) → γ → (γ + (α + B2 + DO3)) phase transition was observed within the austenite matrix. During aging treatment at 400–800 °C, a γ → (γ + κ) → (γ + Cr23C6) → (γ + Cr23C6 + Cr7C3) → (γ + Cr7C3) phase transition was observed within the austenite matrix. When the alloy underwent aging treatment between 400 and 500 °C, some (Fe, Mn)3AlCx) κ-phase carbides formed in the matrix and grain boundaries. A γ → (DO3 + Cr23C6) → (DO3 + Cr23C6 + Cr7C3) → (DO3 + Cr7C3) phase transition was observed on the grain boundaries.