Combined in situ synchrotron micro X-ray diffraction and high-speed imaging on rapidly heated and solidified Ti-48Al under additive manufacturing conditions
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 alpha(2) + gamma microstructure. Upon solidification, the formation of the beta-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. (C) 2015 Elsevier Ltd. All rights reserved.