Microstructure and Properties

The project HyWay aims to promote the design of advanced materials that maintain outstanding mechanical properties while mitigating the impact of hydrogen by developing flexible, efficient tools for multiscale material modelling and characterization. These efficient material assessment suites integrate data-driven approaches, advanced characterization, multiscale modelling, and ontology-based knowledge management seamlessly, revealing hydrogen-material interactions in storage and transport conditions. more

Hydrogen embrittlement remains a strong obstacle to the durability of high-strength structural materials, compromising their performance and longevity in critical engineering applications. Of particular relevance is the effect of mobile and trapped hydrogen at interfaces, such as grain and phase boundaries, since they often determine the material’s performance and can be embrittled by hydrogen enhanced decohesion (HEDE). This study focuses on dual-phase (DP) steels, where ferrite-martensite interfaces play a crucial role in hydrogen embrittlement. Hydrogen absorption triggers complex interactions at these interfaces on the nano- and micro-scale; however, existing studies, especially those addressing the behavior of both mobile and trapped hydrogen, have yielded inconclusive outcomes. more

Titanium and its alloys are widely used in critical applications due to their low density, high specific strength, and excellent corrosion resistance, but their poor plasticity at room temperature limits broader utilization. Introducing hydrogen as a temporary alloying element has been shown to improve plasticity during high-temperature processing, yet the underlying mechanisms remain unclear. more

Hydrogen embrittlement is one of the most substantial issues as we strive for a greener future by transitioning to a hydrogen-based economy. The mechanisms behind material degradation caused by hydrogen embrittlement are poorly understood owing to the elusive nature of hydrogen. Therefore, in the project "In situ Hydrogen Platform for Microstructural Analysis and Mechanical Performance of Materials (HMMM)”, we aim to create a state-of-the-art, all-in-one platform to look more closely into the interactions of hydrogen and the material by utilizing real-time, high-resolution characterization methods. more

In this project, the effects of scratch-induced deformation on the hydrogen embrittlement susceptibility in pearlite is investigated by in-situ nanoscratch test during hydrogen charging, and atomic scale characterization. This project aims at revealing the interaction mechanism between hydrogen and scratch-induced deformation in pearlite. more

This project endeavours to offer comprehensive insights into GB phases and their mechanical responses within both pure Ni and Ni-X (X=Cu, Au, Nb) solid solutions. The outcomes of this research will contribute to the development of mechanism-property diagrams, guiding material design and optimization strategies for various applications. more

This study investigates the mechanical properties of liquid-encapsulated metallic microstructures created using a localized electrodeposition method. By encapsulating liquid within the complex metal microstructures, we explore how the liquid influences compressive and vibrational characteristics, particularly under varying temperatures and strain rate conditions. The findings aim to provide insights into the interactions between liquid and metal in micro-scale structures, expanding the potential applications of this innovative fabrication technique. more

The aim of the work is to develop instrumentation, methodology and protocols to extract the dynamic strength and hardness of micro-/nano- scale materials at high strain rates using an in situ nanomechanical tester capable of indentation up to constant strain rates of up to 100000 s⁻¹. more

This project aims to investigate the dynamic hardness of B2-iron aluminides at high strain rates using an in situ nanomechanical tester capable of indentation up to constant strain rates of up to 100000 s⁻¹ and study the microstructure evolution across strain rate range. more

This project aims to develop a testing methodology for the nano-scale samples inside an SEM using a high-speed nanomechanical low-load sensor (nano-Newton load resolution) and high-speed dark-field differential phase contrast imaging-based scanning transmission electron microscopy (STEM) sensor. more

This project aims to develop a micromechanical metrology technique based on thin film deposition and dewetting to rapidly assess the dynamic thermomechanical behavior of multicomponent alloys. This technique can guide the alloy design process faster than the traditional approach of fabrication of small-scale test samples using FIB milling and subsequent mechanical testing. As a case study for validation, B2-FeAl intermetallic particles are tested at a variety of strain rates and are planned to be tested at high temperatures. more

The aim of the current study is to investigate electrochemical corrosion mechanisms by examining the metal-liquid nanointerfaces. To achieve this, corrosive fluids will be strategically trapped within metal structures using novel additive micro fabrication techniques. Subsequently, the nanointerfaces will be analyzed using cryo-atom probe tomography. more

The aim of the Additive micromanufacturing (AMMicro) project is to fabricate advanced multimaterial/multiphase MEMS devices with superior impact-resistance and self-damage sensing mechanisms. more

“Smaller is stronger” is well known in micromechanics, but the properties far from the quasi-static regime and the nominal temperatures remain unexplored. This research will bridge this gap on how materials behave under the extreme conditions of strain rate and temperature, to enhance fundamental understanding of their deformation mechanisms. The mechanical behavior of different material systems is investigated in a statistically relevant manner using dewetted microparticles as the test-beds. more

Statistical significance in materials science is a challenge that has been trying to overcome by miniaturization as in micropillar compression. However, this process is still limited to 4-5 tests per parameter variance, i.e. Size, orientation, grain size, composition, etc. as the process of fabricating pillars and testing has to be done one by one. With this project, we aim to fabricate arrays of well-defined and located pillars of FCC metals with different stacking fault energy, that can be tested in an automated manner. With a statistically significant amount of samples tested per parameter variance, we expect to apply more complex statistical models and implement machine learning techniques to analyze this complex problem. more

In this project, we study the atomistic structure and phase transformations of tilt grain boundaries in Cu by using aberration-corrected scanning transmission electron microscope to build a relation to the transport properties of the grain boundaries via macroscopic tracer diffusion experiments. In the meantime, we address the impact of the grain boundary bicrystallography and solute segregation on both the grain boundary structure and diffusion properties. more

Hydrogen is a clean energy source as its combustion yields  only water and heat. However, as hydrogen prefers to accumulate in the concentrated stress region of metallic materials, a few ppm Hydrogen can already cause the unexpected sudden brittle failure, the so-called “hydrogen embrittlement”. The difficulties in directly tracking hydrogen limits the analysis to post-mortem probes ignoring hydrogen migration before and during testing, leading to debates about the governing mechanisms. Therefore, a more comprehensive understanding of hydrogen-metal interaction with microstructural features is necessary to prevent hydrogen-introduced damage and further contribute insights into developing hydrogen-resistant materials. more

International research team develops steel for liquid gas transport and storage. Results now published in the journal Science. more

Biological materials in nature have a lot to teach us when in comes to creating tough bio-inspired designs. This project aims to explore the unknown impact mitigation mechanisms of the muskox head (ovibus moschatus) at several length scales and use this gained knowledge to develop a novel mesoscale (10 µm to 1000 µm) metamaterial that can mimic the high energy absorption characteristics of the muskox head without failure between strain rates of 0.001/s and 1000/s. more

The atomic arrangements in extended planar defects in different types of Laves phases is studied by high-resolution scanning transmission electron microscopy. To understand the role of such defect phases for hydrogen storage, their interaction with hydrogen will be investigated. more