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This is a material driven study that explores how post-processing of a 3D-printed biocomposite may increase its utility in the public furniture industry. The study thereby aims to contribute insights in material development and inspire a shift in practices that pushes the industry towards a more sustainable design process. By studying theories on sustainable development, biocomposites, and additive manufacturing, the surface defects in large-scale 3D-printing are put in relation to the industry-specific requirements placed on public furnishings. The potentials for the biocomposite to satisfy these demands are assessed using the four actions steps of material driven design. This includes hands-on exploration of several post-processing methods to minimize the material’s distinctive surface roughness. The most effective surface treatment, a combination of subtractive and additive processing, is subsequently applied in a product development phase to exemplify the feasibility of these methods in the context of furniture. This resulted in a design concept which, although a time-consuming process, proves the possibility of post-processing to influence the ability of the material to meet the requirements for public use. The increased material utility achieved in this study should, however, be considered relative to the economic and ecological consequenses associated with biocomposite processing.

Additive manufacturing has become a very popular and well mentioned technique in recent years. The technique, where 3 dimensional (3D) printing is included, creates opportunities to develop new designs and processing systems. As a research institute within the forest based processes and products, Innventia AB has an idea of combining 3D printing with cellulose. The addition of cellulose will increase the proportion of renewable raw material contributing to more sustainable products. However, when cellulose is added the composition of the filaments changes. The main aim for the project is to devise methodologies to improve properties of composite filaments used for 3D printing. Filament in 3D printing refers to a thread-like object made of different materials, such as PLA and ABS, that is used for printing processes. A literature study was combined with an extensive experimental study including extrusion, 3D printing and a new technique that was tested including 3D scanning for comparing the printed models with each other. The extruding material consisted of polypropylene and cellulose at different ratios, and filaments were produced for 3D printing. The important parameters for extruding the material in question was recorded. Because the commingled material (PPC) was in limited amount, UPM Formi granulates, consisting of the same substances, was used first in both the extrusion and printing process. Pure polypropylene filaments were also created in order to strengthen the fact that polypropylene is dimensional unstable and by the addition of cellulose, the dimensional instability will decrease. After producing filaments, simple 3D models were designed and printed using a 3D printing machine from Ultimaker. Before starting to print, the 3D model needed to be translated into layer-by-layer data with a software named Cura. Many parameters were vital during printing with pure polypropylene, UPM and PPC. These parameters were varied during the attempts and marked down for later studies. With the new technique, in which 3D scanning was included, the 3D printed models were compared with the original model in Cura in order to overlook the deformation and shape difference. The 3D scanner used was from Matter and Form. Photographs of the printed models, results from the 3D scanner, and screenshots on the model in Cura were meshed together, in different angles, using a free application named PicsArt. The result and conclusion obtained from all three parts of the experimental study was that polypropylene’s dimensional stability was improved after the addition of cellulose, and the 3D printed models’ deformation greatly decreased. However, the brittleness increased with the increased ratio of cellulose in the filaments and 3D models. / Additiv tillverkning har på den senare tiden blivit en mycket populär och omtalad teknik. Tekniken, där tredimensionell (3D) utskrivning ingår, ger möjligheter att skapa ny design och framställningstekniker. Som ett forskningsinstitut inom massa- och pappersindustrin har Innventia AB en ny idé om att kombinera 3D-utskrivning med cellulosa. Detta för att höja andelen förnybar råvara som leder till mer hållbara produkter. Dock kommer filamentens sammansättning vid tillsättning av cellulosa att ändras. Det främsta syftet med detta projekt är att hitta metoder för att förbättra egenskaperna hos de kompositfilament som används för 3D-utskrifter. Filament inom 3D-utskrivning är det trådlika objektet gjort av olika material, såsom PLA och ABS, som används vid utskrivningsprocessen. En enkel litteraturstudie kombinerades med en experimentell studie. Det experimentella arbetet var i fokus i detta projekt som omfattade extrudering, 3D-utskrivning samt en ny teknik som prövades, där 3D-scanning ingick, för att jämföra de utskrivna modellerna med varandra. Extruderingsmaterialet bestod av polypropen och cellulosa av olika halter, och av detta material tillverkades filament för 3D-utskrivning. De viktiga parametrarna för extrudering med det önskade materialet antecknades. Eftersom mängden cominglat material (PPC) var begränsat, användes först UPM Formi granuler, som består av samma substanser som i PPC, i både extruderingen och utskrivningen. Filament av ren polypropen tillverkades också för att stärka det faktum att polypropen är dimensionellt instabil. Genom att tillsätta cellulosa minskades dimensionsinstabiliteten. Efter att filamenten hade tillverkats, designades enkla 3D-modeller för utskrivning med en 3D-utskrivare från Ultimaker. Innan utskrivningen kunde börja behövde 3D-modellen bli översatt till lager-på-lager-data med hjälp av en programvara vid namn Cura. Många parametrar är viktiga vid utskrivning med ren polypropen, UPM samt PPC. Temperatur och hastighet varierades för de olika försöken och antecknades för senare studier.Med den nya tekniken, där 3D-scanning ingår, jämfördes de utskrivna 3D-modellerna med originalmodellen i Cura för att se över deformationen och formskillnaden. Den 3D-scanner som användes kom från Matter and Form. Fotografier på de utskrivna modellerna, resultaten från 3D-scannern och bilder på modellerna i Cura sammanfogades i olika vinklar med hjälp av ett gratisprogram som heter PicsArt. Det resultat som erhölls och den slutsats som kunde dras utifrån alla tre delarna av den experimentella studien var att polypropens dimensionsinstabilitet minskades efter tillsatsen av cellulosa, och att de 3D-utskrivna modellernas deformation minskade kraftigt. Skörheten ökade ju högre halt cellulosa som filamenten och de utskrivna modellerna innehöll.

Additive manufacturing (AM) is identified as one of the best techniques in manufacturing components addressing most of the current challenges including material scarcity, design complexity, material compatibility, etc. Stainless steel 316L is one of the promising material candidates in AM due to its extraordinary properties that are useful in a wide variety of industries. Tailoring desired properties locally is heavily investigated in metal AM. This project focuses on investigating the plastic behavior of additively manufactured SS 316L parts printed using laser powder bed fusion (LPBF) specifically to have a strong crystal orientation towards the direction of loading. Parts were printed to have (100), (110), and fiber texture perpendicular to the tensile axis by changing the laser scanning direction. In-situ tensile tests were carried out in a Scanning Electron Microscope (SEM) acquiring electron backscatter diffraction (EBSD) data from the specimen at several strain levels. Schmid Factor (SF) maps, Kernel Average Misorientation (KAM) maps, and Grain orientation spread (GOS) maps were generated using EBSD data. Micromechanisms in plastic deformation of these highly textured AM parts were analyzed based on the crystal orientation and the microstructure. When the influence of crystallographic texture on the micromechanisms of plastic deformation was observed, it was confirmed that a significant difference is present in tensile properties directed with the crystal orientation. During plastic deformation, the crystals were heavily rotated to accommodate slip formations. The slips that are generated at the grains with fiber texture are restricted by the grain boundaries and therefore, showed a higher yield strength. The (100) texture was less prone to plastic deformation. The grains with (110) crystal orientation proved a higher ductility with a perfect slip starting at the grains with higher SFs and showed {111} <110> slip systems.

Wire-arc additive manufacturing (WAAM) is becoming increasingly common for large scale additive manufacturing (AM) applications because of its high deposition rate (2-3 kg/hr.). The rapid temperature changes and subsequent evolution of mechanical properties during AM can lead to large distortion and residual stresses. Finite element modeling of the AM process shows promise to minimize part distortion and residual stresses through improved path planning and process parameter optimization. However, accurate material properties of M250 before and after heat treatment are needed to properly characterize the property evolution from annealed to AM, to aged. Due to limited data on annealed M250, this research presents the mechanical response of solution annealed M250 maraging steel. Testing at temperatures up to 900 degrees Celsius and strain rates from quasi-static to 1 s-1 was performed to provide more representative mechanical properties for AM parts and provide a correlation between AM, aged, and annealed M250 maraging steel.

Selective laser melting of nitrogen gas atomized 17-4PH stainless results in up to 50% lower yield strength and 600% higher elongation compared to traditionally processed, wrought 17-4PH. This drastic difference in mechanical properties is commonly attributed to the presence of high volume fractions of retained austenite within the as-built microstructure. The factors leading to the increased level of retained austenite have not been clarified in the literature. Furthermore, the amount of retained austenite reported within published literature vary widely, even with the use of identical process parameters. Manufacturers of selective laser melting systems state that solution annealing and precipitation hardening will achieve traditional mechanical properties, thereby removing all retained austenite. Once again, it is not clear, how the recommended solution and precipitation treatments lead to the desired changes in microstructure. The research within this thesis establishes that there is up to 0.12wt% higher nitrogen content within additively manufactured 17-4PH, compared to traditionally manufactured 17-4PH, as a result of the powder atomization process. The increased nitrogen is able to stabilize the austenitic phase by reducing the Ms temperature below ambient temperatures. Fertiscope bulk phase analysis demonstrates that the processing atmosphere during selective laser melting cannot alter the fraction of retained austenite in the as-built material. The depression of the Ms temperature in the printed parts is confirmed by dilatometry. Due to the TRIP phenomenon, during sample preparation, it was found that the austenite would transform to 80% martensite at the surface. This transformation will greatly impact the phases detected when x-ray diffraction is used for analysis, leading to a wide variety of reported retained austenite values within literature. A mechanism based on the precipitation of nitrides during solution-treatment has been proposed to explain how heat-treatment of the printed parts can lead to a martensitic microstructure with comparable mechanical properties to those of wrought alloys. / Thesis / Master of Applied Science (MASc) / 17-4PH stainless steel is a martensitic alloy, that can be precipitation hardened when used in traditional manufacturing processes. Within a selective laser melting process, it will exhibit up to 50% lower yield strength and 600% higher elongation. This behaviour is caused by retained austenite, which is stabilized by the introduction of nitrogen during the powder atomization process. As a result, the alloy exhibits transformation induced plasticity. Existing literature states the alloy’s microstructure can be controlled by altering the selective laser melting process atmosphere or using heat treatment to achieve traditional mechanical properties. However, the production and preparation of samples generates a surface transformation which was misinterpreted as a complete bulk transformation. Therefore, the change in microstructure from altering the process atmosphere is only detectable through surface analytical techniques. It is proposed that the rapid cooling rates of SLM form a non-equilibrium state, keeping nitrogen in solution. Subsequent heat treatment allows the formation of nitrides resulting in the Ms being brought above room temperature.

Additive friction stir deposition (AFSD) is an emerging solid-state additive manufacturing process that leverages the friction stir principle to deposit porosity-free material. The unique flow of material that allows for the transformation of bar stock into a near-net shape part is driven by the non-linear heat generation mechanisms of plastic deformation and sliding frictional heat generation. The magnitude of these mechanisms, and hence the total applied thermal power, implicitly depend on the thermal state of the system, forcing power input to become a dependent variable. This is not the case in other 3D printing methods; thermal power can be controlled independently. In this work, the heat generation in AFSD is explored, and its transfer is quantified. In particular, the time-dependent ratio between the amount of conduction into the AFSD tool versus into the substrate is quantified. It was found for the conditions tested with a single-piece AFSD tool, conduction up the tool was on the order of the conduction into the stir. For a more modern three-piece tool, the ratio between the tool and the substrate varied between 0.3-0.1. It was also found that traversing faster resulted in more heat flux into the substrate as would be expected by moving heat source modeling. The total heat generated was also quantified as being equal to between 60% and 80% of the mechanical spindle power depending on the tool type and the exact process conditions. That ratio was found to be time-invariant. At the same time, this changing heat flux ratio was shown to dramatically alter thermocouple measurements in the tool, showing the uncertainty of that method of process control. The contact state between the stir and the tool was treated as a thin conductive layer and a contact heat transfer coefficient was calculated on the order of 20 frac{kW}{m^2K}. The limitations of this treatment were found to occur when a significant amount of the heat generation came from frictional heating rather than plastic deformation. This implies that any measurement conducted in the tool is related to the stir by a complex function driven by the state of the stir; showcasing the need for more well-understood in-situ monitoring. Finally, some of the ideas about thermal control are applied to a case study on the repair of corroded through holes using AFSD to restore fatigue life. It was found that modifying the thermal boundary conditions and applying active cooling at the end of the repair could improve the fatigue life drastically. This was due to less time spent in a thermally active region leading to less heterogeneous nucleation and less grain boundary nucleation. This more preferred microstructure morphology led to a change in the fracture mode and increased the number of cycles to crack initiation and the number of cycles after crack initiation. / Doctor of Philosophy / Metal 3D printing of industrially relevant aluminum alloys is plagued with problems. Additive friction stir deposition seems well posed to overcome some of the problems associated with aluminum printing. Being able to 3D print these alloys with properties that are as good as traditional manufacturing offers a large potential cost and time savings over traditional manufacturing for the aerospace industry (e.g. Boeing, Lockheed Martin, U.S. Navy). For these components to be part of a plane, the manufacturer must prove the components were made the same way print-to-print regardless of the actual shape of the component being made. This dissertation focuses on the key metallurgical variable of temperature and explores how thermal energy is generated and where that energy goes in to the system. The key takeaway is, that without precise knowledge of the total heat generated and the entire thermal system, assurances about processing temperature cannot be made. An exploration of heat generation and metrics about its dispersion are presented. This is followed by a study on repairing structural components while changing the thermal system to understand its effects.

The information contained in this thesis explores ways to develop a habitat for human settlement on Mars. Currently, most designs for living on Mars focus primarily on survival and emphasize the technological aspects necessary for sustaining life. However, there is a lack of holistic consideration for what life on Mars would entail beyond mere survival. These existing designs are understandably geared towards astronauts who will spend only a few months on Mars. In contrast, this project is dedicated to envisioning the future of Mars settlement, aiming to support astronauts who intend to permanently live and establish communities on Mars, ultimately transforming them into Martians. The project adopts a human-centric approach by integrating biophilic design principles to enhance the well-being of future Martian inhabitants. It seeks to address potential psychological challenges that settlers on Mars may encounter, offering innovative solutions rooted in biophilia. This approach aims to create environments that foster connection with nature, promote mental health, and support overall quality of life for individuals living on Mars. Humans have evolved over millions of years to thrive on Earth, and many of our primal instincts are deeply rooted in our hunter-gatherer ancestry. Transitioning humans to live on another planet would uproot them from their natural environment, potentially depriving them of these primal instincts and causing psychological challenges. (Szocik, n.d.) This project aims to address these issues through architectural solutions. By designing habitats that consider and accommodate our innate instincts and connections to nature, we can mitigate the psychological impacts of living on a different planet. The goal is to create environments on Mars that resonate with our evolutionary heritage, fostering psychological well-being and adaptation in extra-terrestrial settlements. / Master of Architecture / This thesis looks at how to create a habitat for humans to live on Mars. Right now, most designs focus mainly on survival and the technology needed to sustain life. Most don't really consider what everyday life would be like beyond just staying alive. Most current designs are for astronauts who will only be on Mars for a few months. This project, however, imagines a future where people live on Mars permanently and form communities, essentially becoming Martians. The project uses a design method that focuses on human needs at a subconscious and psychological level. It incorporates biophilic design principles, which emphasize our connection to nature, to improve the well-being of future Martian inhabitants. This approach aims to address psychological challenges that settlers on Mars might face, offering innovative solutions based on biophilia. The goal is to create environments that foster a connection with nature, promote mental health, and support a good quality of life. Humans have evolved over millions of years to live on Earth, and many of our basic instincts are tied to our hunter-gatherer ancestors. Moving to another planet could take us away from our natural environment and cause psychological challenges. This project aims to tackle these issues through thoughtful architectural design. By creating habitats that consider our natural instincts and connections to nature, we can reduce the psychological impacts of living on Mars. The goal is to design environments that align with our evolutionary background, helping people adapt and thrive in extra-terrestrial settlements.