Metastable intermetallic phase precipitation from supersaturated Co solid solution and the consequences on microstructure evolution
The precipitation of intermetallic phases from a supersaturated Co(Nb) solid solution is studied in a cooperation with the Hokkaido University of Science, Sapporo.
These investigations show that the formation of metastable, coherent L12 NbCo3 strongly affects the microstructural evolution and growth of the equilibrium phase Nb2Co7. While these metastable fine L12 precipitates always form on directly cooling from the single-phase solid solution range to room temperature, their clearly visible formation reaction can be circumvented by an intermediate annealing step below the solvus temperature. This annealing results in a Widmannstätten-type microstructure with fine plates of the equilibrium Nb2Co7 phase in a Co matrix as shown in Fig. 1.
International researcher team presents a novel microstructure design strategy for lean medium-manganese steels with optimized properties in the journal Science
The key to the design and construction of advanced materials with tailored mechanical properties is nano- and micro-scale plasticity. Significant influence also exists in shaping the mechanical behavior of materials on small length scales.
This project is part of Correlative atomic structural and compositional investigations on Co and CoNi-based superalloys as a part of SFB/Transregio 103 project “Superalloy Single Crystals”. This project deals with the identifying the local atomic diffusional mechanisms occurring during creep of new Co and Co/Ni based superalloys by correlative…
A wide range of steels is nowadays used in Additive Manufacturing (AM). The different matrix microstructure components and phases such as austenite, ferrite, and martensite as well as the various precipitation phases such as intermetallic precipitates and carbides generally equip steels with a huge variability in microstructure and properties.
Many important phenomena occurring in polycrystalline materials under large plastic strain, like microstructure, deformation localization and in-grain texture evolution can be predicted by high-resolution modeling of crystals. Unfortunately, the simulation mesh gets distorted during the deformation because of the heterogeneity of the plastic…
Hydrogen embrittlement (HE) is one of the most dangerous embrittlement problems in metallic materials and advanced high-strength steels (AHSS) are particularly prone to HE with the presence of only a few parts-per-million of H. However, the HE mechanisms in these materials remain elusive, especially for the lightweight steels where the composition…
With the support of DFG, in this project the interaction of H with mechanical, chemical and electrochemical properties in ferritic Fe-based alloys is investigated by the means of in-situ nanoindentation, which can characterize the mechanical behavior of independent features within a material upon the simultaneous charge of H.