The Ternary System Iron-Chromium-Molybdenum at 1200°F

The phase boundaries of the iron-chromium-molybdenum ternary system. have been investigated at 1200° F. One-hundred and eighty alloys were prepared by the method of powder metallurgy for this study. The alloys ware aged in vacuum (10-4 mm Hg or better) for ten days at 1200° F. Following the aging treatment the alloys were rapidly cooled to room temperature. The primary research tools were the methods of X-ray diffraction and microscopy as applied to the determination of phase boundaries in alloy systems. Microhardness tests ware used in conjunction with microscopy for the identification of phases for some alloys. The results of the present investigation in the three binary systems are compared with the results of previous investigators. It was found that the sigma phase or the Fe-Cr binary system is stabilized by the addition of molybdenum and that this brittle phase is present over a large range of compositions.