Combined in situ synchrotron micro X-ray diffraction and high-speed imaging on rapidly heated and solidified Ti–48Al under additive manufacturing conditions

Abstract

An in situ method to study the behavior of alloys during rapid heating and cooling combining laser heating with synchrotron micro X-ray diffraction and high-speed imaging is presented. Near-spherical Ti–48Al specimens were melted using a laser-based heating system consisting of two diode lasers and subsequently rapidly solidified using a Cu support structure. The Al-rich Ti–48Al forms a fine grained dual phase α2+γ microstructure. Upon solidification, the formation of the β-phase is fully suppressed. Time-resolved peak evolution and temperature-corrected micro X-ray diffraction data provides clear observations of solidification and solid state phase transformations under non-equilibrium conditions similar to beam-based additive manufacturing.