Influence of Process Conditions on the Local Solidification and Microstructure During Laser Metal Deposition of an Intermetallic TiAl Alloy (GE4822)

Metallurgical and Materials Transactions A, vol. 52, pp. 1106–1116

Abstract

Abstract Temperature-time cycles are essential for the formation of microstructures and thus the mechanical properties of materials. In additive manufacturing, components undergo changing temperature regimes because of the track- and layer-wise build-up. Because of the high brittleness of titanium aluminides, preheating is used to prevent cracking. This also effects the thermal history. In the present study, local solidification conditions during the additive manufacturing process of Ti-48Al-2Cr-2Nb with laser metal deposition (LMD) are investigated by both simulation and experimental investigations. Dependencies of the build-up height, preheating temperatures, process parameters and effects on the resulting microstructure are considered, including the heat treatment. Solidification conditions are found to be dependent on the build height and thus actual preheating temperature, process parameters and location in the melt pool. Influences on both chemical composition and microstructure are observed. Resulting differences can almost be balanced through post heat treatment.

Authors 2

1. Silja‐Katharina Rittinghaus corresponding Aachen Fraunhofer Institute for Laser Technology ILT

   Fraunhofer Institute for Laser Technology

   Affiliation as printed

   Fraunhofer Institute for Laser Technology ILT, Steinbachstr. 15, 52074, Aachen, Germany

2. Jonas Zielinski Aachen

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University—Digital Additive Production, Campus Boulevard 79, 52072, Aachen, Germany