Chair for Materials Science and Engineering

Micromechanical and microstructural investigations of intermetallics and Ni-base superalloys.

Yordan Kalchev investigates the local mechanical properties of Ni-base superalloys for applications as blade materials in gas turbines. Moreover, he investigates novel model materials such as compositionally complex alloys (CCAs), which are often referred to as high-entropy alloys (HEAs). Nanoindentation and micro-compression tests are performed, where possible, in-situ in a scanning electron microscope. An effort is made to explore whether some of these tests can be performed at elevated tempatures, in the temperature range from 400 to 1000°C. Special emphasis is put on effects that can be attributed to changes in alloy composition and microstructure. Relating mechanical materials behavior on the microscale to elementary microstructural processes is in the center of Yordan Kalchev’s work, who uses advanced analytical electron microscopy (SEM and TEM) in combination with X-ray spectroscopy for scale bridging microstructural characterization. Emphasis is also put on the phase stability of selected HEAs.