Phase discrimination between ? and ? phases in the new nickel-based superalloy VDM Alloy 780 using EBSD

VDM Alloy 780 is a new nickel-based superalloy developed for higher service temperatures up to 750 °C. In addition fine ??-Ni3(Al,Ti) strengthening precipitates, grain boundary precipitates resembling ?-Ni3Nb and/or ?-Ni3Ti phases are also observed in this alloy. Previous studies on 718Plus, with chemical composition close 780, revealed that phase discrimination between ? and ? particles not straightforward requires the use of high-resolution characterization techniques such as HRTEM. This work aims at evaluating EBSD technique regards identification these plate-shaped particles. Classical indexing diffraction patterns based Kikuchi band detection Hough space fails differentiate two phases. However approaches comparison experimental simulated patterns, least partly, could overcome issue. The advanced dictionary-based approach involves simulation dynamic electron scattering events identified main component consistent recently published HRTEM investigation 780. Refinement classical method under kinematic assumptions implemented “Refined Accuracy” mode Oxford AZtec software package led appreciable improvement.