Topic: Laser-based welding of steels and aluminium alloys.
Supervisor: Knut Marthinsen
The Postdoc project (2024-2026)
Laser-based welding of aluminium alloys. This project aims to enhance the reliability and efficiency of laser-based welding in industrial applications by reducing defects, minimizing rework, and improving weld quality through advanced process control, monitoring technologies, and numerical modeling.
Methods
Mechanical characterization of the samples will be performed to evaluate the welding process. Numerical finite element modelling will be conducted to understand the deformation performance of the welded joints.
Expected impact for industry
This project will contribute to improved weld quality, reduced production costs, and enhanced process efficiency, facilitating the wider adoption of laser welding in industrial manufacturing.
Background
Phd’s degree in physical metallurgy from NTNU. Topic: Deformation behavior of Aluminum alloys – Work Hardening and Portevin-Le Chatelier (PLC) effect.
PhD Candidates
William Frønning Thyholdt
Topic: Through-Process Modelling of Aluminium Alloys
Supervisor: Bjørn Holmedal
The PhD project (2025-2029)
Developing a deeper understanding of the mechanisms of recrystallization specifically during processing.
Dynamic recrystallization during extrusion
Methods
Both modeling and lab work will be performed. Models can be developed using machine learning or finite element methods. In the lab the models can be tested using the Gleeble machine, mechanical tests and SEM.
Expected impact for industry
A better understanding of microstructure mechanics during processing of aluminium alloys can help industries design new materials and production pathways. This could lead to better tailoring of material properties or more efficient production.
Background
Master’s degree in Chemical Engineering and Biotechnology from NTNU. Topic: Electrowinning of Fly Ash Leachate.
Armel Perrotin
Topic: Engineering of Aluminium-Silicides alloys for additive manufacturing applications
Supervisor: Marisa Di Sabatino
The PhD project (2025-2028)
Improve the understanding of the process and material parameters that make a powdered aluminium-silicium alloy suitable for additive manufacturing (AM) applications
Methods
The main characterization techniques used for this work will be scanning electron microscopy (SEM) for the particles microstructure, as well as chemical analysis like glow discharge mass spectrometry (GD-MS) and Fourier transform infrared spectroscopy (FT-IR).
Expected impact for industry
Additive manufacturing of aluminium-silicides has huge potential for scale up on an industrial level but lacks understanding on which alloy composition would produce the best parts for a wide range of applications
Background
Master’s degree in Green Chemistry, Catalysis and Environment from Université de Poitiers (France).
Topic: Catalyst preparation and characterization for Ozone and Volatile Organic Compounds (VOC) removal for aircraft air purification.
Topic: In-situ TEM investigations of precipitates in Al-Zn-Mg-(Cu) alloys
Supervisor: Randi Holmestad
The PhD project (2025-2028)
This PhD project aims to investigate the phase transition from solute clusters to precipitates in 7xxx series aluminium alloys using in-situ TEM.
ADF micrograph showing the grain boundary of a 7003.52 alloy.
Numerous precipitates are visible, both along the grain boundary
(intergranular) and within the grains themselves (intragranular).
Methods
The application of in-situ TEM will enable real-time observation and quantification of precipitate evolution in Al-Zn-Mg-(Cu) aluminium alloys. Sample preparation will be conducted using FIB, ensuring site-specific lamellae suitable for dynamic TEM studies.
Expected impact for industry
The Al-Zn-Mg-(Cu) alloys are widely used in applications demanding high mechanical strength, such as the aerospace sector. This project will contribute to a deeper understanding of precipitation mechanisms in these alloys and support the optimization of mechanical performance by tuning the elemental composition and thermomechanical treatment.
Background
Master’s degree in Nanotechnology from NTNU. Topic: “Strain and magnetic domain analysis of gallium ion-induced nanomagnets using SPED and LM-STEM-DPC”.
Jan Konkel
Topic: Development of Low Transformation Temperature (LTT) Steel Alloys for Welding and Additive Manufacturing Applications
Supervisor: Tomas Manik
The PhD project (2024-2027)
Utilization of the low martensite start temperature for LTT alloys and the occurring volume expansion during the austenite-martensite transformation to remove residual stresses in the heat-affected zone and optimize the crack formation resistance in the weld area.
Residual stress distribution in a welded butt joint in longitudinal
and transversal direction. llustration by U. Zerbst, 2020.
Methods
Fabrication of welded components using LTT filler wires and subsequent microstructural characterization including light optical microscopy, SEM, EBSD analysis, residual stress assessment and mechanical properties measurements, e.g. dilatometry, hardness and tensile testing.
Expected impact for industry
LTT filler wires can be used to increase the fatigue resistance in welded constructions. This leads to an enhanced lifetime, improved structural integrity and reduced manufacturing costs due to the avoidance of post-weld treatment of the components
Background
Master’s degree in Materials Science and Engineering from NTNU.
Topic: Effect of Conventional and Screw Extrusion on the Properties of AA1370 Aluminum Process Scrap and End-of-Life Scrap Material.
Topic: The effect of deformation on 6xxx Al-alloys
Supervisor: Randi Holmestad
The PhD project (2024-2027)
Nano-structure characterization of microstructure evolution in extruded 6xxx Al-alloys during deformation by cold rolling.
Methods
The main focus of the project will be on transmission electron microscopy (TEM) using techniques such as bright field, dark field, high-resolution TEM and high-angle annular dark field scanning TEM (HAADF-STEM) to characterize different alloys and process routes.
Expected impact for industry
Combining plastic deformation with thermal ageing for extruded 6xxx Al-alloys has shown an improvement in mechanical properties, including mechanical strength and strength-ductility balance. Understanding and implementing new thermo-mechanical routes gives a significant potential for growth for both standard and recycling-friendly 6xxx alloys.
Background
Master’s degree in applied physics from NTNU. Topic: Characterization of gas atomized Si and NiSiV powders.
Topic: The Corrosion protection of floating structures using laser welding technology
Supervisor: Nima Razavi
The PhD project (2024-2027)
To optimizing laser cladding process with corrosion resistance alloy on bridge structure which can provide corrosion protection and meet the expected 100-year life.
Methods
Laser cladding of corrosion resistance alloy on S420ML, Parameter optimization, microstructure characterization: optical microscopy and SEM, mechanical testing, followed by corrosion analysis.
Expected impact for industry
This project is important for bridge and offshore structure for enhancing its corrosion life without need for regular maintenance, repair and inspection.
Background
Master’s degree in Materials Engineering from NIT Karnataka, Surathakal, India. Topic: Autogenous Diode Laser Welding of Fe-Ni based superalloy materials of A-286 & INCOLOY-800.
Topic: The effect of trace elements on recycled Al Alloys
Supervisor: Marisa Di Sabatino
The PhD project (2023-2026)
To understand the role of impurities on different recycled HPDC (High Pressure Die Casting) Al alloys and their properties.
Schematic view of the HPDC process.
Illustration by T. Nallusamy et al, 2021.
Methods
The main focus will be on the characterization of the microstructural-, chemical-, and mechanical properties. Some of the techniques that will be used are: Scanning electron microscopy (SEM), Transmission Electron Microscopy (TEM), Glow Discharge Mass Spectrometry (GDMS), Hardness, and Tensile strength.
Expected impact for industry
Recycled Al alloys can be used in automotive components to save energy consumption and reduce weight and CO2 emissions.
Background
Master’s degree in Physics from Department of Physics at NTNU. Topic: TEM characterization of Strontium Barium Niobate (SrxBa1-xNb2O6) thin films.
Topic: Advanced nanoscale characterization of grain boundary segregation in metals.
Supervisor: Yanjun Li
The PhD project (2023-2026)
Study segregation of solute atoms to grain boundaries in aluminium alloys using state-of-the-art characterization techniques. Solute atoms are known to influence grain boundary behavior and to affect properties such as strength, corrosion and recyclability.
A bright field TEM image of a grain
boundary in a 6xxx aluminium alloy
Methods
Samples of grain boundaries will be created using focused ion beam microscopy (FIB), these samples will then be studied using atom probe tomography (APT) and transmission electron microscopy (TEM).
Expected impact for industry
Increased understanding of the effect of solute grain boundary segregation, aiding in alloy design and recyclability. Experimental data can be used to validate and develop atomic scale simulations for alloy design.
Background
Master’s degree in Nanotechnology from NTNU. Topic: TEM studies of precipitates in HYB welded Al-Mg-Si-Cu.
Topic: The effect of trace elements on the microstructure development and mechanical properties of cast irons.
Supervisor: Marisa Di Sabatino
The PhD project (2021-2025)
To understand the role and effect of trace elements on the microstructure and properties of ductile cast iron as more recycled steel scraps are added in the industry to reduce costs and CO2 footprint.
Methods
Scanning electron microscopy (SEM) and secondary ion mass spectrometry (SIMS), mechanical testing, thermal analysis (TA), etc. to study the microstructure, chemistry, and mechanical properties of the ductile cast iron.
Expected impact for industry
This project is important for the cast iron industry who produces sustainable and environmentally friendly ductile cast iron components for applications such as windmills, automotive, pipes and pumps etc.
Background
Master’s degree in physical metallurgy from NTNU. Topic: Welding of aluminium.
Topic: Development of nanoparticle- containing aluminum filler wires
Supervisor: Ida Westermann
The PhD project (2021-2025)
Development of nanoparticle-containing aluminum filler wires for fusion welding by molten salt-assisted flux casting, extrusion, and cold drawing. Slimmer and more environmentally friendly structures may be manufactured if the weakest link behavior in aluminum fusion welding can be solved.
Methods
Investigation of the TiC nanoparticles' microstructural influence during processing and the mechanical properties of the weld zone.
Expected impact for industry
High-strength aluminum alloys could enable lighter cars in the automotive industry. The produced filler wires could also be used in other fusion processing methods, such as wire arc additive manufacturing.
Background
Master’s degree in physical metallurgy from NTNU. Topic: Durable Aluminum-Reinforced Environmentally-friendly Concrete Construction (DARE2C).
Topic: Multiscale studies/advanced characterization (e.g. TEM/ SEM) of materials joints
Supervisor: Randi Holmestad
The PhD project (2021-2023)
TEM studies of aluminium welds where nanoparticles have been added to increase the strength of the welds. The welded regions are the weakest link in the aluminium product. Adding of nanoparticles to study how this can improve the material.
Methods
High resolution TEM studies of nanoparticles. Different measurement techniques will be used (high resolution imaging, scanning precession electron diffraction (SPED), scanning transmission electron microscopy (STEM), energy dispersive X-ray spectroscopy (EDS).
Expected impact for industry
Recycling of materials is crucial for a greener future. If the aluminium welds can be made stronger through adding nanoparticles, the use and reuse of aluminium can be increased.
Background
Master’s degree in physics from NTNU. Topic: Transmission electron microscopy (TEM) studies of heterostructured GaAs/GaAsSb nanowires.
Topic: Develop precipitation model with improved nucleation concepts, addressing the influence of impurity elements, vacancy and atom clustering kinetics
Supervisor: Yanjun Li
The PhD project (2021-2025)
Development of an advanced precipitation model for AA6xxx alloys with significantly improved nucleation kinetics of precipitates in both bulk of grains and at grain boundaries. To address the influences of impurity elements and vacancies on the age hardening response of recycling-based aluminium alloys.
Methods
Develop numerical microstructure model based on thermodynamics and kinetics of phase transitions and diffusion of vacancies and solutes; Use KMC, DFT and Thermo-Calc simulation to calculate necessary thermodynamic and kinetic data; Couple strength model to predict the mechanical properties of Al-Mg-Si alloys.
Expected impact for industry
To provide an effective modelling tool for industry, which is important for alloy design and heat treatment parameter optimization especially for recycle-based AA6xxx alloys.
Background
Master’s degree in mechanical engineering from Southeast University, China. Topic: Numerical modelling of dendritic growth in aluminium melt.
Topic: Material development and microstructure control for powder based additive manufacturing processes
Supervisor: Tomas Manik
The PhD project (2021-2025)
To study material development and microstructure control for powder based additive manufacturing (AM) processes with the ambition of expanding the material range for AM including the use of recycled (powder) materials.
Methods
Modelling of microstructure to i) favor the columnar to equiaxed transition and ii) the impact of alloying elements on cracking tendency, and experimental work to investigate some materials that show promising properties indicated by the models.
Expected impact for industry
The results can be used by industries that work with the specific alloys or that are interested in the methodology of investigating potential alloy systems to eliminate poor candidates at an early stage of researching it.
Background
Master’s degree in Material Science for Energy and Nanotechnology from University of Oslo. Topic: The Al-Zn-Mg-Cu alloy system alloyed with silicon.
Trond Arne Hassel (Disputation 28 November 2024)
Topic: Microstructure and properties of duplex stainless steel manufactured by directed energy deposition.
Supervisor: Knut Sørby
The PhD project (2021-24)
Use a coaxial directed energy deposition additive manufacturing system to produce duplex stainless steel parts and characterise the achieved properties. The goal is to produce material that matches or exceeds the properties of conventionally manufactured duplex.
Microstructure of additively manufactured
duplex.
Methods
Additive manufacturing of duplex stainless steels by DED-LB/wire and heat treatment followed by characterisation with mechanical testing, light optical microscopy and SEM.
Expected impact for industry
This project is important for the oil and gas, maritime and process industries, who use duplex components. By enabling manufacturing of high-quality spare parts by additive manufacturing, the lead time for replacement components can be reduced considerably.
Background
Master’s degree in physical metallurgy from NTNU. Topic: Microstructure, strength and hardness in F22 steel.
