Phase transformations in Fe_1-2xAl_xV_x (x≤0.15) alloys

Iron rich Fe-Al-V alloys have a considerable potential as structural materials at high temperatures. In previous works we have studied the phase equilibria in the bcc system Fe-Al-V, from computational thermodynamics calculations. There, the vertical section Fe_1-2XAl_XV_X was defined as the best candidate to design alloys with technological application, due to its wide (A2+L2₁) two-phase field. In this paper, experimental techniques of Differential Scanning Calorimetry (DSC) and Transmission Electron Microscopy (TEM) are used to find the phase equilibria in Fe_1-2XAl_XV_X section up to 1100 °C and X≤0.15. The A2/B2 order-disorder transformation was confirmed, the limits of two-phase fields (A2+L2₁) and (L2₁+B2) with L2₁ as coherent precipitate were established, and evidence of a small (A2+B2) field previously unknown was found. The experimental assessment of these phase equilibria opens the way to the design of these alloys and their possible heat treatments.