I am Anna-Maria Persson and I started my PhD at the 1st of February this year. My study is related to the field of mechanical properties of thermoplastic elastomers in injection moulded components. My PhD is a SINTEF Material and Chemistry funded industrial PhD, associated to SFI Manufacturing and admitted by NTNU.

I started my PhD with experimental studies of the elasto-visco-plastic response of a novel but commercialised thermoplastic elastomer prepared by vulcanization (TPV). One significant aspect is sample preparation and geometry (figure 1), and another is handling and treating the experimental data (strain) output. As the experimental methodology in itself is a target for the PhD, a selected few more materials will be studied subsequently.
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Figure 1A and 1B: Speckle patterns for digital image correlation giving 3D field strain measurements of cyclic compression tests.
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In parallel, materials models are intended calibrated and verified, primarily for a selection of published material models, including behavioural features of non-linear nature and time-temperature dependency. I am currently immerged in 10-15 years of publications of rubber and elastomer material models. One major challenge is to adequately describe the complex mechanical response with a model also suitable for industrial use. Figure 2 is an example of one characteristic of elastomer mechanical response.

During my PhD, I will have a close dialogue with Kongsberg Automotive's Couplings division to get the valuable industrial view feedback (figure 4). To develop a response on how an integrated, free-geometry elastomer sealing can compete with a conventional o-ring in a demanding application, the material models will be used in simulation of two component injection moulded sealings. After this, the elastomer sealing performance needs to be related to the performance of a conventional rubber sealing (figure 3.)
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Hi, I am Tina and I started my PhD in the fall of 2016. During my PhD, I will characterize the interface in joined materials, first and foremost joined aluminium and steel.

My background is from the nanotechnology study programme at NTNU. During my Master’s thesis work I used transmission electron microscopy (TEM) to study silicon carbide (SiC) from Saint-Gobain in Lillesand. With a transmission electron microscope, I can determine the crystal structure and composition of the investigated material. These characteristics determine the material’s mechanical properties and are thus important from an industrial perspective.
 
The joining of aluminium and steel
The research project that my PhD is a part of focuses on the development of multi-material products that combine desirable properties of the parent materials. First and foremost, the joining of aluminium and steel will be investigated, which is important where the combination of high strength and low weight is essential.

​My role in this project is to use TEM to characterise the interface between aluminium and steel. Several different intermetallic compounds are found here, that influence the properties of the joint. I aim to get a thorough understanding of the interface and to link its characteristics at the microscopic scale back to the properties of the joint on the macroscopic scale.

Collaboration with other PhD candidates 
I will collaborate closely with two other PhD candidates, Siri Marthe Arbo and Muhammad Zeeshan Khalid, who also work on this project. Siri Marthe works on the joining process itself and will provide me with samples for characterisation, while Zeeshan will use some of my data as input and starting parameters to perform simulations.

First months of my PhD
So far, I have been studying a sample made by SINTEF Chemistry and Materials, where aluminium and steel were joined using a cold metal transfer technique. For the next three years I will explore samples made from different aluminium and steel alloys and different joining techniques. I am excited to continue to improve on techniques within TEM and to get new and useful insights into these materials’ characteristics.
 
Thank you for reading and have a happy new year!

Hi, my name is Muhammad Zeeshan Khalid and I am the fourth PhD student that will be working with SFI Manufacturing. During my PhD, I will focus on atomistic modelling of multi-material interfaces.

I did my Master in Applied Physics from University of engineering and technology, Pakistan. During my master, I worked on many different areas and developed extensive knowledge about doing research. My master thesis was based on the mathematical modelling of high temperature thermal energy storage system for solar thermal power plant applications. I also worked on the analytical mathematical methodology to solve partial differential equations to simulate thermal energy storage model.

PhD position
I authored two review articles, which not only shaped my thinking about research fields, but also helped me to develop analytical and scientific writing skills. I also got an opportunity to review papers from renowned journals IEEE Transactions on Sustainable Energy and International Journal of Energy Research. After getting such good experience in research field, I became motivated and enthusiastic to pursue my career in this direction, so I started to look for PhD positions. I applied for a PhD position at NTNU Gjøvik in May 2016, and I got the position and started in October 2016.

Atomistic modelling of multi-material interfaces
My PhD thesis topic is Atomistic modelling of multi-material interfaces. My PhD is part of a large project working on Multi-Material Products and Processes in SFI Manufacturing. Part of this project is experimentally working on the interfacial microstructure and mechanical properties of dissimilar materials in Trondheim. Where they are using high definition microscopic images to study the properties of dissimilar materials using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and HAADF-STEM techniques. PhD candidates involved in this experimental study are Siri Marthe Arbo and Tina Bergh. Experimental input provided by Siri Marthe and/or Tina are used to run DFT calculations to study nanostructure material’s interface properties. I am responsible for the DFT calculations to extrapolate experimental data.

Nanostructure changes mechanism 
The basic motivation of an improved understanding of these nanostructured materials is the need to develop further use of efficient and lightweight technologies for automotive industry, aerospace, aviation, shipbuilding, railway and transportation industries, to not only perform efficiently, but also use less fuel to minimize the consumption cost. My project provides the basic information about the nanostructure changes mechanism during the welding of dissimilar materials to help experimentalist to improve their welding methodologies. My initial plan is to study the interfaces of aluminum and steel using density functional theory approach by developing atomistic model using the transmission electron microscopy (TEM) images.

1st month of my PhD
During my 1st month of my PhD, I worked on my PhD project description and read a lot of literature. I also met with some of the good researchers in my field, who gave me some important insights and ideas to develop my understanding. Therefore, I am hopeful, the next three years of my PhD will be very productive and useful. I am really excited and looking forward to the next three learning years as a PhD candidate.
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Siri Marthe Arbo started her PhD in August 2015. During her PhD, she will look at primarily two dissimilar metals, steel and aluminium, and she will try to find a new way of joining the two metals together. Below she will give you an update about her everyday life as a PhD candidate in SFI Manufacturing.

A lot of trying and failing have filled my first months as a PhD candidate, as well as a lot of paperwork, spending hours writing my project description and teaching duties – however, this means that no day is equal!

How does a typical day look like?
A typical day starts with spending too many minutes going through my mail, drinking some coffee and going over what has to be done that day. I have a four-year PhD, which means that I have teaching duties at the university, helping first and second year chemistry students with laboratory exercises in different chemistry courses.

This semester I am working with the students taking a laboratory course in Inorganic chemistry, so a typical day for me usually including spending one or more hours during my day, preparing for the next experiments that we are going to perform, correcting the reports from last time or spending my afternoon in the laboratory helping out with the experiments. This is a lot of fun, but also a bit challenging from time to time. However, I am learning a lot from my teaching duties and it makes my weeks more fun and interesting.

And the rest of the week?
The rest of my week will be spend on my own project. I can be all from trying to find new interesting articles, reading up on  the literature or planning my next experiments. Last month we performed some initial compression tests of our aluminum and steel samples, in order to study how the aluminum and steel deforms compared to the deformation we have observed in the simulations. These samples needs to be metallographically prepared so that I can study them using light microscopy and scanning electron microscopy.

​Some days I will spend in the laboratory, trying to find the optimal sample preparation method for the samples and to improve my own sample preparation skills. Other days, I spend more time on different tasks that we need to perform, such as risk assessment of our project, obligatory PhD courses or planning my semester abroad.

What are you working on at the moment?
At the moment, we are soon ready to perform the first initial tests where we combine the compression already studied with rotation. The goal is to systematically vary the different process parameters and study how these affect the joining of the two metals. We have, based on simulations and guessing come up with a test plan, which I am putting the final touches on.

We have received the samples from the workshop and now we are waiting for everything to come together before we begin. These tests are very important for my work and will decide where to go from here, and what we should first of all focus on!