Speaker
Description
Additive manufacturing makes it possible to produce highly complex components such as turbine blades with integrated cooling channels directly from a digital 3D CAD model. However, the material selection of nickel-base superalloys for the laser powder bed fusion (LPBF) process is limited to a few alloys that reveal a high printability, such as IN625 or IN718. These alloys, however, exhibit only moderate high-temperature and creep properties compared to nickel-base superalloys with higher γ′-content, such as CM247LC, that currently cannot be produced crack-free via LPBF.
Based on an industrially widely used but not yet printable reference alloy CM247LC, adjustments to the chemical composition (e.g., C, Hf, Ti, Al content) are made to improve processability with LPBF. High-throughput CALPHAD-based screening is applied to pre-select promising chemical compositions from a multidimensional alloy space with respect to specific target properties to accelerate alloy development significantly. In the following, the melt pool geometries, 3D temperature distributions, cooling rates, and thermal gradients during the LPBF process of selected alloy compositions are simulated with CFD-melt pool simulations. The melt pool simulation results are essential to simulate the solidification behavior and microstructure development of adapted AM nickel-base superalloys with high γ′-content by a phase-field approach in the following. Based on the computational alloy design approach, strategies for improving the processability of high γ′ nickel-base superalloys are discussed.