Atomic scale understanding of the TRIP-assisted dual-phase high-entropy alloys
In this project, we aim to achieve an atomic scale understanding about the structure and phase transformation process in the dual-phase high-entropy alloys (HEAs) with transformation induced plasticity (TRIP) effect. Aberration-corrected scanning transmission electron microscopy (TEM) techniques are being applied to obtain the related information at atomic resolution.
The displacive phase transformation from face-centered cubic (FCC) γ phase to hexagonal close-packed (HCP) ε martensite and the reverse transformation (ε→γ) play a key role in enhancing the mechanical properties of FCC alloys, especially for the recently developed TRIP-assisted dual-phase HEAs. These phase transformations strongly depend on the stacking fault energy, instant temperature and stress condition during mechanical loading.
Within the statistical limits of TEM and energy dispersive spectroscopy (EDS), no indication for solute segregation and precipitation were found at interface between FCC γ and HCP ɛ phase in the dual-phase HEA. In the deformed samples, a mixed sub-structure consisting of γ nano-lamellas and twins was observed in HCP ɛ block. We also investigated the local displacive phase transformation at annealing twin boundaries in the dual-phase HEA. A systematic study is being carried out to understand the atomic structure of such annealing twin boundaries and the corresponding effect on phase transformation process.
International researcher team presents a novel microstructure design strategy for lean medium-manganese steels with optimized properties in the journal Science
Laser Powder Bed Fusion (LPBF) is the most commonly used Additive Manufacturing processes. One of its biggest advantages it offers is to exploit its inherent specific process characteristics, namely the decoupling the solidification rate from the parts´volume, for novel materials with superior physical and mechanical properties. One prominet…
In this project we study the development of a maraging steel alloy consisting of Fe, Ni and Al, that shows pronounced response to the intrinsic heat treatment imposed during Laser Additive Manufacturing (LAM). Without any further heat treatment, it was possible to produce a maraging steel that is intrinsically precipitation strengthened by an…