Design of transformation-induced plasticity-assisted dual-phase high-entropy alloys
In this project, we employ a metastability-engineering strategy to design bulk high-entropy alloys (HEAs) with multiple compositionally equivalent high-entropy phases.
HEAs are originally proposed to benefit from phase-stabilization through entropy-maximization. Yet, the concept is overturned in this project by designing a massive solid solution strengthened, transformation-induced plasticity-assisted, dual-phase HEA (TRIP-DP-HEA). We decrease phase stability to achieve two key benefits: (i) interface hardening due to a dual-phase microstructure (that results from reduced thermal-stability of the high temperature phase); (ii) transformation-induced hardening (that results from the reduced mechanical-stability of the room temperature phase). This combines the best of two worlds: extensive hardening of advanced steels owing to decreased phase stability, and massive solid solution strengthening of HEAs.
About 90% of all mechanical service failures are caused by fatigue. Avoiding fatigue failure requires addressing the wide knowledge gap regarding the micromechanical processes governing damage under cyclic loading, which may be fundamentally different from that under static loading. This is particularly true for deformation-induced martensitic…
In this project, we investigate the phase transformation and twinning mechanisms in a typical interstitial high-entropy alloy (iHEA) via in-situ and interrupted in-situ tensile testing ...
Solitonic excitations with topological properties in charge density waves may be used as information carriers in novel types of information processing.
Oxides find broad applications as catalysts or in electronic components, however are generally brittle materials where dislocations are difficult to activate in the covalent rigid lattice. Here, the link between plasticity and fracture is critical for wide-scale application of functional oxide materials.
In this project we conduct together with Dr. Sandlöbes at RWTH Aachen and the department of Prof. Neugebauer ab initio calculations for designing new Mg – Li alloys. Ab initio calculations can accurately predict basic structural, mechanical, and functional properties using only the atomic composition as a basis.
Low dimensional electronic systems, featuring charge density waves and collective excitations, are highly interesting from a fundamental point of view. These systems support novel types of interfaces, such as phase boundaries between metals and charge density waves.
Enabling a ‘hydrogen economy’ requires developing fuel cells satisfying economic constraints, reasonable operating costs and long-term stability. The fuel cell is an electrochemical device that converts chemical energy into electricity by recombining water from H2 and O2, allowing to generate environmentally-friendly power for e.g. cars or houses…