After finishing my master degree the spring 2014 in Materials Science and Technology I decided to devote three more years at NTNU as a PhD candidate at the Department of Engineering Design and Materials (IPM). Initially, the thought of continuing with a PhD, had been going through my head sometimes, but was not an established part of my plan. Mainly because I thought it was unachievable considering the high requirements and challenges.
However, during my last year as a master student, I had a supervisor, Prof. Dr. Christian Thaulow, with a great enthusiasm and encouragement, who helped me to see the fun and inspiration in science. After some discussions and considerations, I knew I wanted to exploit the possibilities to develop my knowledge and confidence within research and improve my abilities to understand and solve problems. Thus, I was convinced that a PhD was something for me. I had to put some extra effort in obtaining good grades and finally apply for the PhD position that was relevant for my background.
My PhD work is a part of a larger project called “Arctic Materials” where SINTEF has the project leadership with several partners involved. The main goal of the project is to establish criteria and solutions for safe and cost-effective application of materials (mainly steel) for exploration in Arctic regions. Materials meet several challenges in an Arctic environment. Wind, sea waves, drifting icebergs and icing of constructions are some of the challenges that can result in high construction loads. In combination with the extreme low temperatures, this gives the toughest requirements to the materials mechanical performance, fracture resistance and lifetime integrity.
In order to predict the materials behavior under these conditions, material characterization at the smallest scale is necessary. And this is where I come in. During the last year, I have been investigating material properties at nano-and micrometer scale, where I perform micro-compression tests on small cylindrical samples, also referred to as “pillars”, which are machined on the material surface by removing surrounding material. In the images below you can see a series of pillars machined on the surface of my test material, which is temporary iron, and one deformed pillar after a compression test.
Micro-compression testing is widely used within the field of nanomechanics. These small pillars have a diameter of 1 micrometer or smaller (depending on the purpose of the experiment). To understand how small this is you can consider a single hair from your head, which have a diameter of 70-100 micrometer. Considering the small size, advanced technology is required to work with these nanostructures.
During the compression tests of the pillars, compression data are continuously recorded during the test, and material properties can be calculated from these data. Moreover, we are able to observe how the pillars are deformed during testing. Hence, it’s possible to analyze how the atoms in the material interact with each other during the deformation. Since the test material is relevant for “Arctic Materials”, it is necessary to investigate the mechanical response at low temperatures as well.
Therefore, extensive work was put into developing a cooling system interfaced with the rest of the equipment, with the capability to cool down the material to temperatures as low as -90 °C. The extreme temperature we are working with here, is actually as cold as the world’s temperature record at Antarctic.
Such low temperatures could freeze a humans eyes, nose and lungs within minutes. Of course, we are not exposed to the low temperature during experiments since are sample is kept in a vacuum chamber and is cooled down by a connection from a small container containing liquid nitrogen.
In order to operate with the equipment and understand the experimental results, training and experience is an important factor. I am so lucky to have these helpful coworkers who have trained me and shared their knowledge with me. At the moment, I’m sharing office with Håkon Gundersen, Dr. Bjørn Rune Sørås Rogne and Jørn Skogsrud and a lot of springtails (which is mainly Håkon`s pets used for investigation, stored in our office fridge).
Behind these walls, there are a lot interesting conversations, including everything from advanced material science to statistics of number of clementine segments in one clementine. All of us have the pleasure to be guided by our supervisor Prof. Dr. Christian Thaulow, which is also supervising several master students that we work closely with. Together we are working as research group, where all our projects are somehow related to each other, making a great benefit for each other’s work. Hopefully, some of these master students will continue with a PhD. I’m impressed how much they have accomplished during this semester, and think they have a lot to offer in a PhD.
This is just a small part of my daily life at IPM. I’m looking forward to the continuation of my PhD work, were I expect late evenings at the lab, hours of writing, trials and failures, but also development of myself as a scientist, and enjoyment moment of obtaining successful results that could be beneficial for “Arctic Materials” to exploit the large Arctic areas in a safety and cost-efficient way.
Wish me luck! 🙂
This blog entry was written by PhD Candidate Anette Brocks Hagen, at NTNU – The Department of Engineering Design and Materials