Abstract:
As new alloys are being developed for additive manufacturing (AM) applications, questions related to the temperature-dependent structural and compositional stability of these alloys remain. The accuracy of calculation of phase diagrams (CALPHAD) predictions was tested with energy-dispersive X-ray diffraction (ED-XRD) on electrostatically levitated samples at high temperatures. This technique led to several advantages over other XRD techniques, primarily being the simultaneous measurement of composition through X-ray Fluorescence (XRF) emissions. A set of alloys composed of 3d transition metals was tested. It is found that while experimental results agreed qualitatively with CALPHAD predictions for many binary and ternary alloys, they proved inaccurate for more complex alloys, such as the CoCrFeNi quaternary. Additionally, XRF measurements showed that of the alloys tested, those containing Cu became Cu deficient at high temperatures. This leads to questions on the viability of these alloys for certain AM processes.