Host

Vrije Universiteit Brussel, VUB, Brussels, Belgium

Objectives

The main objective of the research is to study the relationship between the formed interphases in metal AM repair approaches and the resulting atmospheric corrosion behaviour and Stress Corrosion Cracking (SCC) of the repaired metal, in relation to the AM printing conditions and thermal post-processing. To achieve this challenging objective, the specific aims are as follows:

• To determine the microstructure, composition, and the metallurgical phenomena of the formed interphases during WAAM printing, as a function of printing parameters and post-processing heat treatments, for two selected alloys.
• To identify the key parameters that define the interphase – corrosion relationship.
• To characterize the mechanical properties of the materials in collaboration with DC2 at NOVA

Supervisor: Iris De Graeve

Host

NOVA-University of Lisbon, Portugal

Objectives

The main aim is the implementation of a thermodynamically oriented framework for selection of specific compositions for repair of large structural components based on widely used ferrous and Ni-base alloys towards their application in demanding service conditions and the mechanical performance analyses. The objectives are:

• Develop new WAAM-based technology for multi-feeding wire to enabled accessible exploration of large compositional spaces towards the validation of the thermodynamic framework.
• Comprehensively characterize the microstructure, mechanical properties, and corrosion behaviour (link with DC1) of the repaired components, with special emphasis on the interfacial characteristics, while correlating them to the processing conditions.
• Understand the mechanical failure mechanisms, especially within the mixed region of the WAAM-repaired components, while obtaining microstructure information of specific key features collaboration with VUB.

Host

RISE, Sweden, with PhD awarded by VUB, Brussels, Belgium

Objectives

The main objective of this IRP is to study the relationship between metallic components produced with different AM techniques and the material properties such as the susceptibility to hydrogen embrittlement, the mechanical durability, and the corrosion resistance in the marine environment, where the metallic components are subjected to mechanical stresses, moving assemblies, degradation stresses, cathodic protection and fouling. No standardized guidelines for use of AM materials exists for the blue economy sector, which this work will aim to contribute to (with a standardization expert from the EAB as mentor for DC3). To achieve this challenging objective, the specific aims are:

• To determine the surface & bulk metal microstructure and composition, of the different AM techniques.
• To determine the susceptibility to hydrogen embrittlement as a function of AM processes and post-processing such as heat treatments.
• Study of fatigue and fatigue corrosion and mechanical properties as a function of manufacturing processes of the selected alloys.
• Using the hybrid test platform (ML based) developed in VALIDHTP (EU Project No 101006927)

Host

Helmholtz Centrum HEREON, Geesthacht, Germany, with PhD awarded by Kiel University, Kiel, Germany

Objectives

This work will focus on machine-learning guided development of evenly degrading magnesium alloys for bioresorbable implants. In particular, we aim at understanding the influence of WAAM (Wire-Arc-Additive-Manufacturing) fabrication process parameters (e.g., wire composition, diameter, arc discharge voltage and time, cooling rate) on the degradation profile of produced metallic materials (rate and especially the extent of localized corrosion). The aim is to establish relevant process-structure-property relationship and identify the optimal fabrication parameters for uniformly degrading Mg alloys without compromising the mechanical properties. Samples produced will be tested using custom-made Robotic Testing Platform. A data-driven machine-learning model will be developed to determine the impact of the individual process parameters on the selected set of target properties and validated for predicting the properties of untested material. Mechanistic understanding of the driving forces of localized corrosion will be achieved by performing model experiments on selected magnesium scaffolds. A unique combination of spatially resolved electrochemical and surface characterization methods will characterize Mg scaffolds exposed to the simulated body fluid environment.

Research stays are planned at NOVA University Lisbon (Portugal), RISE (Sweden) and Cortronik (Germany).

Supervisors: Prof. Dr. Mikhail Zheludkevich, Dr. Sviatlana Lamaka and Dr. Christian Feiler.

https://www.hereon.de/institutes/surface_science/index.php.en 

Host

Vrije Universiteit Brussel, VUB, Brussels, Belgium

Objectives

The main objective of the research is to study the relationship between the surface and in-depth composition, thickness, microstructure and interface properties of metallic functional coatings applied by AM on conventional metal substrates (e.g., Inconel coating on steel substrate) and the resulting corrosion behaviour, in relation to the AM conditions and thermal post-processing. To achieve this, the specific aims are:

• To determine the surface & bulk metal microstructure and composition, and the metallurgical phenomena of the formed interphases between AM metal functional coating and the conventional metal substrate, as a function of AM parameters and heat treatments.
• To study the corrosion mechanisms of the AM functionalized metal substrate
• To identify the key parameters that define the AM functional coating characteristics – corrosion relationship.
• To collaborate with the PhD at NOVA (DC6) for sample fabrication and mechanical properties.

Supervisor: Iris De Graeve

The primary goal is the development of deposition strategies for coating metallic components fabricated by WAAM. Key objectives include:

• Deposit different coatings (considering different target applications focusing on improved wear, corrosion and/or fatigue resistance, for example) onto metallic components using wire and arc additive manufacturing. These coating can be deposited with gradients of composition to further improve the functionally and applicability of the deposited coatings.
• Unveil the microstructure/properties relationships that ensure improved and optimized response, so that the coating can ensure increased lifetime and durability of the coated component.
• In-situ characterization during mechanical testing using synchrotron-based measurements will be used to characterize the cracking behaviour under different thermomechanical solicitations.

AM leads to totally new microstructures that result in unique corrosion behaviour. This corrosion, mostly caused by (micro-)galvanic coupling of phases with different compositions / nobility, will be experimentally characterised in WP1 and WP2 for AM fabricated and repaired metal alloys, as well as for AM coatings on metal alloys. The objective of this project is:

• To define and collect the needed parameters from the experimental analyses (potential differences, polarisation curves etc.) as input for the FEM.
• To develop and validate the FEM of the corrosion behaviour using initially established models, and then adapting them to AM microstructures.

Supervisor: Iris De Graeve 

Host

Technische Universität DRESDEN, Germany 

Objectives

Various modelling approaches have been proposed to link the microstructure to mechanical properties of the material. One of the most promising approaches is the phase field crystal (PFC) or its coarse-grained amplitude expansion (APFC) model. It allows for atomistic resolution but operates on diffusive time scales. Recent developments allow to parameterize these models for specific materials. The objective of this project is to develop these models and simulate with realistic microstructures and appropriate material specific approximations.  

This contains research visits at Warwick (UK) and Gothenburg (Sweden). 

Background 

You should have a Master degree in Mechanics, Mathematics or Physics, knowledge on the numerical solution of partial differential equations by finite elements and decent knowledge on scientific programming, preferably in C++.  

Supervisor: Prof. Dr. Axel Voigt  

https://tu-dresden.de/mn/math/wir 

Host

University of Gothenburg (Gothenburg, Sweden) 

Objectives

The project aims to utilize biocomposites as coatings for metallic components produced via Wire Arc Additive Manufacturing (WAAM). These biocomposites are sensitive to humidity due to moisture absorption in their bio-polymeric matrices and natural reinforcements. Our objectives are as follows: 

• Develop accurate computational models capable of describing the moisture diffusion process in these materials, accounting for their complex microstructure. We will create microscale and multiscale models to simulate moisture diffusion, considering both matrix and reinforcement properties. 
• Enhance the computational efficiency of these high-fidelity multiscale models using Machine Learning techniques, specifically Artificial Neural Networks (ANN). 

• Utilize the ANN-enhanced micromechanical and multiscale models to design biocomposites with desired moisture absorption properties. This approach enables the creation of new material microstructures without the need for costly and time-consuming experimental procedures. 

By achieving these objectives, we aim to advance the use of biocomposites as effective coatings for WAAM-produced metallic components, optimizing their moisture-related properties, and reducing the reliance on extensive experimental testing. 

Supervisor: Mohsen Mirkhalaf (https://www.gu.se/en/about/find-staff/mohsenmirkhalaf) 

Research Group: https://www.gu.se/en/research/mechanics-of-materials   

Host

University of WARWICK, United Kingdom

Objectives

In this project, you will train and validate machine-learned interatomic potentials (MLIPs) for exemplar AM metals using active learning techniques. These MLIPs can then be used to simulate fracture. Coupled with time acceleration techniques such as adaptive Monte Carlo, the long-timescale evolution of cracks under cyclic loading conditions will permit the study of fatigue crack growth.

Background: Additively manufactured (AM) metals present a range of new opportunities and challenges that need to be understood across the scales. For example, AM parts have smaller grains and thus a higher density of grain boundaries than metals from traditional manufacturing, leading to more sites for cracks, reduced toughness and plasticity and increased residual stresses. This could make these materials susceptible to fatigue cracking, where repeated loading cycles lead to eventual failure of the material. Existing codes that rely primarily on empirical data to assess fracture mechanics and standards are not suited for these materials and may lead to either over- or under-conservative assessments. While atom-scale models could describe the processes at the crack front with sufficient precision, the timescales of fatigue crack growth so far remain beyond their capabilities.

Supervisors and Research Environment: Prof. James Kermode and Dr Peter Brommer are based in the Multiscale Materials Modelling Laboratory (M3L) in the Warwick Centre for Predictive Modelling (WCPM) in the School of Engineering at the University of Warwick in the United Kingdom. Prof. Kermode has extensive experience modelling fracture at the atomic scale and developing MLIPs, while Dr Brommer is an expert in the use of adaptive Monte Carlo approaches. The PhD student working on this project will benefit from the vibrant cross-departmental research environment associated with WCPM and with the EPSRC Centre for Doctoral Training in Modelling of Heterogenous Systems (HetSys), which provides an allied cohort of PhD students working on related projects, as well as from Warwick’s excellent high performance computing facilities.

Collaboration: Outcomes from this project will also be used to inform mesoscale models such as the phase field crystal models of DC8. The student will also work with DC5 to validate fracture results experimentally. Internships in both TU Dresden and VUB are planned to carry out these collaborative aspects.