This project is a joint project of the De Magnete group and the Atom Probe Tomography group, and was initiated by MPIE’s participation in the CRC TR 270 HOMMAGE. We also benefit from additional collaborations with the “Machine-learning based data extraction from APT” project and the Defect Chemistry and Spectroscopy group.
Magnetic materials are key components of energy conversion devices and thus improving the material’s magnetic properties is critical to enhance the sustainability of power generation and conversion. We use atom probe tomography (APT) to study the relationship between the microstructure on the nanoscale and the properties of various soft and hard magnetic materials. As demonstrated by experiments and machine-learning aided analysis, the changes in magnetic properties, e.g., magnetization, coercivity, Curie temperature and domain structure, are closely related to the variation of magnets’ microstructure. Our results help guide the design of magnetic materials.
Several magnetic systems are currently under active investigation: NdFeB, Sm(Co,Fe), CeCoCu magnets as hard magnetic alloys and CoFeNiTaAl high-entropy alloys as soft magnets.
Fig: APT 3D map of the Sm2(Co,Fe,Cu,Zr)17 show different spatial arrangement of the three phases depending on the region: magnetic Cu-rich (blue) and Zr-rich (green) cell boundary phases inside Fe-rich matrix cell phase (grey).
Fig: APT 3D map of the Sm2(Co,Fe,Cu,Zr)17 show different spatial arrangement of the three phases depending on the region: magnetic Cu-rich (blue) and Zr-rich (green) cell boundary phases inside Fe-rich matrix cell phase (grey).
The objective of the project is to investigate grain boundary precipitation in comparison to bulk precipitation in a model Al-Zn-Mg-Cu alloy during aging.
The thorough, mechanism-based, quantitative understanding of dislocation-grain boundary interactions is a central aim of the Nano- and Micromechanics group of the MPIE [1-8]. For this purpose, we isolate a single defined grain boundary in micron-sized sample. Subsequently, we measure and compare the uniaxial compression properties with respect to…
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…
Hydrogen embrittlement (HE) of steel is a great challenge in engineering applications. However, the HE mechanisms are not fully understood. Conventional studies of HE are mostly based on post mortem observations of the microstructure evolution and those results can be misleading due to intermediate H diffusion. Therefore, experiments with a…
Understanding the deformation mechanisms observed in high performance materials, such as superalloys, allows us to design strategies for the development of materials exhibiting enhanced performance. In this project, we focus on the combination of structural information gained from electron microscopy and compositional measurements from atom probe…
Understanding hydrogen-microstructure interactions in metallic alloys and composites is a key issue in the development of low-carbon-emission energy by e.g. fuel cells, or the prevention of detrimental phenomena such as hydrogen embrittlement. We develop and test infrastructure, through in-situ nanoindentation and related techniques, to study…
3D copper microarchitectures will be fabricated using a localized electrodeposition-based microscale additive manufacturing process and mechanically tested under extreme strain rates. Structures to be tested range from simple micropillars to complex microlattices. The suitability of such full-metal architectures towards energy absorption and…
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 AM, parts are built from layer by layer fusion of raw material (eg. wire, powder etc.). Such layer by layer application of heat results in a time-temperature profile which is fundamentally different from any of the contemporary heat treatments.
Previous work in the group has established that this unique thermal profile can be exploited for microstructural modifications (eg. clustering, precipitation) during manufacturing. The aim of this work is to develop a fundamental understanding of such a strongly non-linear, peak-like thermal history on the precipitation kinetics.
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…
