Pressure and heat: Testing alloys for gas turbines

© Frank Kümmel, FRM II/TUM

VDM Metals is a high-performance metal provider. In the HiMat project,1 together with the Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), VDM tested its VDM® Alloy 780 using a specially developed testing machine at the Research Neutron Source, Heinz Maier-Leibnitz Zentrum (FRM II).

The challenge

Gas turbines must endure extreme conditions, including high forces at temperatures above 600°C. The new nickel VDM® Alloy 780 is resistant to high temperatures and corrosion, making it ideally suited for use in gas turbines. To develop new materials, investigations under operating conditions are required.

The experiment

To replicate the conditions in a gas turbine, a special sample environment is necessary. The new testing machinery generates temperatures of up to 1200°C, and recreates a vacuum or air environment similar to a gas turbine. The testing system also generates forces such as tension or compression on the sample, simulating the large centrifugal forces experienced by a turbine in operation.

While extreme forces were applied to the sample, changes in the alloy were studied using neutrons. In addition, neutrons were used to study the structure of the sample before and after loading to identify pores and cracks.

The results

The experiments at MLZ enabled the research team to better understand the properties of the alloy, providing insight into the material’s structure and how it is affected by high temperatures and forces. With this information, VDM can adapt the manufacturing process to further optimise the alloy.

The good interaction of the three cooperation partners has been very successful: the MLZ as a large-scale research facility with the FRM II neutron source and the FAU Erlangen with its special knowledge in microstructures and methods that complement us, and finally the industrial partner VDM Metals, which is further developing the alloy.

Frank Kümmel
Advanced Materials Group, MLZ

1. The HiMat project was funded by the German Federal Ministry of Education and Research (BMBF).