There is a great need in the transportation industry for high strength, high stiffness and lightweight materials with excellent dimensional stability. The use of these materials reduces fuel consumption and greenhouse gas emission as well as malfunctioning of components when subjected to fluctuating temperatures. Metal matrix composites (MMCs) are designed to meet these needs of transportation and other industries. However, their use is limited by lack of information on their thermal behaviour. In addition, reactions that occur in MMCs alter their microstructure and properties. These reactions have been widely investigated using X-ray Diffractometry (XRD) and electron microscopy (EM). However, these techniques cannot provide information such as charge transfer and local elemental structures in materials. Synchrotron X-ray Absorption Spectroscopy (XAS) could be used to identify reaction products in MMCs as well as provide information which XRD and EM cannot provide.<p> The thermal behaviour of Al-Mg alloy A535 containing fly ash particles as well as charge transfer and reactivity in particulate aluminium alloy metal matrix composites (MMCs) were investigated in this work. The materials studied were (i) Al-Cu-Mg alloy AA2618 and its composites reinforced with 10 and 15 vol.% alumina (Al2O3) particles and (ii) Al-Mg alloy A535 and its composites reinforced with a mixture of 5 wt.% fly ash and 5 wt.% silicon carbide, 10 wt.% and 15 wt.% fly ash. The investigative techniques used included Differential Scanning Calorimetry (DSC), Thermomechanical Analysis (TMA), Optical Microscopy (OM), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), and synchrotron X-ray Absorption Spectroscopy (XAS).<p> The results obtained showed that the coefficient of thermal expansion (CTE) of A535 decreased with the addition of fly ash and silicon carbide. Also, the addition of these particles improved the dimensional stability of the alloy in that the residual strain, åp, cycling strain, åc, and CTE decreased. The results obtained from XAS measurements showed evidence of charge redistribution in the aluminium in AA2618 with the addition of alumina particles. The results obtained from XAS measurements showed evidence of charge redistribution in the aluminium in AA2618 with the addition of alumina particles. The addition of alumina particles into AA2618 increased the p-orbital population and also changed the surface chemistry of the matrix. It was also demonstrated that the XAS technique can be used to determine the presence of various oxides in industrial fly ash and spinel (MgAl2O4) in alumina and fly ash particles extracted from the MMCs.

Thermal mismatch between different components of a system could cause of problems like residual stress induced cracking, thermal fatigue or even optical misalignment in certain high technology applications. Use of materials with customized thermal expansion coefficient is a counter-measure to resolve such problems. Zirconium tungstate (ZrW2O8) with negative thermal expansion coefficient is capable of being used in synthesis of composites with tailored coefficient of thermal expansion (CTE). In this work, the sol-gel method which had been already set up in our group was characterized and the sources of the factors imposing impurities in the product were distinguished in all the steps of precursor preparation and heat treatment. In the second part of study, zirconium tungstate particles synthesized by the sol-gel method were utilized as core in synthesis of ZrW2O8&ndash / ZrO2 core&ndash / shell composite particles. Shell layer was composed of ZrO2 nanocrystallites and precipitated from an aqueous solution by urea hydrolysis. Volume of the shell was effectively controlled by concentration of the initial zirconium ion in the solutions. The rate of precipitation was a function of the ratio of initial urea concentration to zirconium ion. It is hypothesized that isolation of the ZrW2O8 within a layer of ZrO2, will be a key element in solving problems associated with reactivity of ZrW2O8 towards other components in sintering of ceramic&ndash / ceramic composites with tuned or zero thermal expansion coefficient.

The development of steam turbines is continuously moving forward and the aim is oftento develop configurations with higher power output. Siemens Industrial Turbomachinery AB is currently in the beginning of a development project which replaces a single turbine with two interconnected turbines with higher pressure and temperature of the steam than before. To ensure reliable quality and hold down costs is it an advantage to do most of the assembly before delivery to site.This thesis work at Linköping University has been written in collaboration with Siemens Industrial Turbomachinery AB, Finspång. The objective of this work is to investigate the possibility to mount two turbines and a gearbox on a turbine frame. Theframe will be used both for transportation and during operation.The thesis considerate analyses of the turbine layout and critical parameters that may affect a turbine frame. In addition was a frame concept developed and evaluated with respect to solid mechanics and alignment of the shaft arrangement.Our conclusion is that there are good possibilities to install the equipment on a frame and achieve demands due to solid mechanics and alignment of the shaft arrangement.We recommend Siemens Industrial Turbomachinery AB to carry on with the project and do further investigations of the natural frequency of the frame concept, compare financial advantages and disadvantages together with possibilities for transportation.

There is a great need in the transportation industry for high strength, high stiffness and lightweight materials with excellent dimensional stability. The use of these materials reduces fuel consumption and greenhouse gas emission as well as malfunctioning of components when subjected to fluctuating temperatures. Metal matrix composites (MMCs) are designed to meet these needs of transportation and other industries. However, their use is limited by lack of information on their thermal behaviour. In addition, reactions that occur in MMCs alter their microstructure and properties. These reactions have been widely investigated using X-ray Diffractometry (XRD) and electron microscopy (EM). However, these techniques cannot provide information such as charge transfer and local elemental structures in materials. Synchrotron X-ray Absorption Spectroscopy (XAS) could be used to identify reaction products in MMCs as well as provide information which XRD and EM cannot provide.<p> The thermal behaviour of Al-Mg alloy A535 containing fly ash particles as well as charge transfer and reactivity in particulate aluminium alloy metal matrix composites (MMCs) were investigated in this work. The materials studied were (i) Al-Cu-Mg alloy AA2618 and its composites reinforced with 10 and 15 vol.% alumina (Al2O3) particles and (ii) Al-Mg alloy A535 and its composites reinforced with a mixture of 5 wt.% fly ash and 5 wt.% silicon carbide, 10 wt.% and 15 wt.% fly ash. The investigative techniques used included Differential Scanning Calorimetry (DSC), Thermomechanical Analysis (TMA), Optical Microscopy (OM), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), and synchrotron X-ray Absorption Spectroscopy (XAS).<p> The results obtained showed that the coefficient of thermal expansion (CTE) of A535 decreased with the addition of fly ash and silicon carbide. Also, the addition of these particles improved the dimensional stability of the alloy in that the residual strain, åp, cycling strain, åc, and CTE decreased. The results obtained from XAS measurements showed evidence of charge redistribution in the aluminium in AA2618 with the addition of alumina particles. The results obtained from XAS measurements showed evidence of charge redistribution in the aluminium in AA2618 with the addition of alumina particles. The addition of alumina particles into AA2618 increased the p-orbital population and also changed the surface chemistry of the matrix. It was also demonstrated that the XAS technique can be used to determine the presence of various oxides in industrial fly ash and spinel (MgAl2O4) in alumina and fly ash particles extracted from the MMCs.

Thermal mismatch between different components of a system could be sources of problems like residual stress induced cracking, thermal fatigue or even optical misalignment in certain high technology applications. Use of materials with tailored thermal expansion coefficient is a counter-measure to overcome such problems. With its negative thermal expansion coefficient zirconium tungstate (ZrW2O8) is a candidate component to be used in synthesis of composites with controlled thermal expansion coefficient (CTE). ZrW2O8 is typically produced by solid-state reaction between zirconium oxide and tungsten oxide at 1200oC. However, it has been demonstrated that ZrW2O8 can also be synthesized using wet chemical techniques, which provide a superior chemical homogeneity that often extents down to the atomic scale, and the convenient means of controlling nucleation and growth of the primary crystallites. With the commonly adopted wet chemical approaches, it is possible to crystallize particles with sizes in the submicrometer range at temperatures as low as 600 oC or even lower. In these studies, precursors are aged either below 100 oC (7 days &ndash / 3 weeks), or at 160-180 oC under hydrothermal conditions (1&ndash / 2 days). Besides the obvious disadvantage in the ageing steps, use of tungsten sources with high cost in all approaches, constitutes the other disadvantage. Production of composites with tunable controlled thermal expansion (CTE) has been achieved by blending negatively and positively expanding materials in different proportions. In majority of these studies composites have been produced by conventional sintering methods. Spark Plasma Sintering (SPS) is a recent technique / in which sintering can be achieved at relatively low temperatures in short durations. There is only one study made by Kanamori and coworkers on the use of SPS in sintering of a composite, in which ZrW2O8 is one of the constituents [1]. This study aims the synthesis of ZrW2O8 particles and composites that possess tunable or zero CTE. A novel precursor recipe for ZrW2O8 synthesis was developed. In preparation of the precursor a total of 2 days of ageing and a temperature less than 100 oC was used. It was developed using a cost-effective tungsten source, namely tungstic acid and its final pH was lower than 1. The particles obtained from &lsquo / unwashed&rsquo / procedure had sizes in micrometer range, while those obtained from &lsquo / washed&rsquo / case had sizes in the range of 400-600 nm. These precursors could readily be crystallized at 600 oC, which in turn provided the desired particle sizes for composite applications. Experimental details on the precursor development are hereby presented with a discussion on the effects of solution parameters (i.e. solubility of tungstic acid, adjustment of the stoichiometry, ageing time) on the phase purity of the fired product. Zirconium oxide (ZrO2) has positive vi thermal expansion, therefore ZrW2O8/ZrO2 was selected as the composite system, and for their synthesis both conventional and spark plasma sintering methods were experimented. Composition ranges that provide composites with almost zero CTE&rsquo / s were determined. The composite having a composition of containing 35% ZrW2O8, 65% ZrO2, and 35 w/o Al2O3 and sintered at 1200 oC for 24 hours had an expansion coefficient of 0.20 x 10-6/K for conventional method, while the one having a composition of 55% ZrW2O8, 45% ZrO2 and sintered at 1000 oC for 5 minutes had an expansion coefficient of 0.94 x 10-6/K for spark plasma sintering method. For characterization of the products X-ray diffraction (XRD), scanning electron microscopy (SEM), photon correlation spectroscopy (PCS), and thermal and dilatometer analyses (DTA/TGA/DMA) were used.

<p>A paper that shows motion when being exposed to heat has in this study been called a paper muscle. A paper muscle can be used for many different applications, e.g. smart advertisement or indicators in printed paper products. The muscles created in the present work were prepared by gluing or printing a polymer layer onto paper. The polymer layers consisted of MELINEX, MYLAR or toner, which are known to expand when exposed to heat. Furthermore, all three material systems showed bending when exposed to heat.</p><p>A mechanical bilayer model was implemented and used to quantitatively study the parameters that influence the bending of the muscles. The model indicated that the dimensional changes of the polymer layers relative to that of the copy paper was found to be approximately 0,1-0,5 % within the temperature range 23-60 °C. The experiments showed that the combined dimensional changes within the polymer and paper layers were not linear with respect to temperature, and that there was a significant difference in bending for muscles cut in the MD and in the CD. Also, when assuming that the polymer is the active component, the observed coefficient of thermal expansion was a factor ~10 greater compared to published literature data. These findings led to the conclusion that it was indeed the dimensional changes within the paper that were the dominant cause of the bending. This was confirmed by a muscle, comprising a bilayer of paper cut in the MD and the CD, which bended when exposed to heat. The results also indicate that a large part of the bending could be attributed to the hygrocontraction of paper.</p>

The coefficient of thermal expansion (CTE) is one of the major factors responsible for distresses in concrete pavements and structures. Continuously reinforced concrete pavements (CRCPs) in particular are highly susceptible to distresses caused by high CTE in concrete. CRCP is a popular choice across the U.S. and around the world for its long service life and minimal maintenance requirements. CRCP has been built in more than 35 states in the U.S., including Texas. In order to prevent CRCP distresses, the Texas Department of Transportation (TxDOT) has limited the CTE of CRCP concrete to a maximum of 5.5 x10-6 strain/oF (9.9 x10-6 strain/oC). Coarse aggregate sources that produce concrete with CTE higher than the allowable limit are no longer accepted in the TxDOT CRCP projects. Moreover, CTE is an important input in the Mechanistic-Empirical Pavement Design Guide (MEPDG). Small deviations in input CTE can affect the pavement thickness significantly in MEPDG designs. Therefore, accurate determination of concrete CTE is important, as it allows for enhanced concrete structure and pavement design as well as accurate screening of CRCP coarse aggregates. Moreover, optimizing the CTE of concrete according to a structure’s needs can reduce that structure’s cracking potential. This will result in significant savings in repair and rehabilitation costs and will improve the durability and longevity of concrete structures. This study found that the CTEs determined from saturated concrete samples were affected by the internal water pressure. As a result, the TxDOT method yielded higher values than did the American Association of State Highway and Transportation Officials (AASHTO) method. To further investigate the effect of internal water pressure, an analytical model was developed based on the poroelastic phenomenon of concrete. According to the model, porosity, permeability, and the rate of temperature change are the major factors that influence the internal water pressure development. Increasing the permeability of concrete can reduce the internal water pressure development and can thus improve the consistency of measured CTE values. Preconditioning concrete samples by subjecting them to several heating and cooling cycles prior to CTE testing and reducing the rate of temperature change improved the consistency of the CTE test results. Concrete CTE can be reduced by blending low-CTE aggregates with high-CTE aggregates and reducing the cement paste volume. Based on these findings, a concrete CTE optimization technique was developed that provides guidelines for the selection of concrete constituents to achieve target concrete CTE. A concrete proportioning technique was also developed to meet the need for CTE optimization. This concrete proportioning technique can use aggregate from any sources, irrespective of gradation, shape, and texture. The proposed technique has the potential to reduce the cement requirement without sacrificing performance and provides guidelines for multiple coarse and fine aggregate blends. / text

A paper that shows motion when being exposed to heat has in this study been called a paper muscle. A paper muscle can be used for many different applications, e.g. smart advertisement or indicators in printed paper products. The muscles created in the present work were prepared by gluing or printing a polymer layer onto paper. The polymer layers consisted of MELINEX, MYLAR or toner, which are known to expand when exposed to heat. Furthermore, all three material systems showed bending when exposed to heat. A mechanical bilayer model was implemented and used to quantitatively study the parameters that influence the bending of the muscles. The model indicated that the dimensional changes of the polymer layers relative to that of the copy paper was found to be approximately 0,1-0,5 % within the temperature range 23-60 °C. The experiments showed that the combined dimensional changes within the polymer and paper layers were not linear with respect to temperature, and that there was a significant difference in bending for muscles cut in the MD and in the CD. Also, when assuming that the polymer is the active component, the observed coefficient of thermal expansion was a factor ~10 greater compared to published literature data. These findings led to the conclusion that it was indeed the dimensional changes within the paper that were the dominant cause of the bending. This was confirmed by a muscle, comprising a bilayer of paper cut in the MD and the CD, which bended when exposed to heat. The results also indicate that a large part of the bending could be attributed to the hygrocontraction of paper.

The interaction between magnetism and the nuclear lattice is investigated experimentally, using thermal expansion, magnetostriction, specific heat, magnetisation and neutron scattering measurements. Both localised moment systems, as represented by the rare earth compounds Tb2Agln, Pd2Gdln and Cu2Gdln, as well as transition metal compounds, Ni2MnGa and V20 3 have been characterised at low temperatures. Measurements of the lattice properties are important due to the intrinsic coupling of magnetic degrees of freedom to them. The response of the lattice to magnetic order, and also to applied magnetic fields have been probed by the use of the aforementioned techniques. Such techniques allow the direct determination of the coefficient of linear thermal expansion, over a wide temperature range and the forced magnetostriclion in applied fields of 0 to 7T. Indirect determination of the spontaneous magnetostriction and the total magnetic entropy contribution via measurements of isostructural compounds further enhance the range of experimental data available. The dynamic properties are characterised by spin polarised neutron scattering measurements. The experimental results are presented and discussed. Various methods of coupling lattice and electronic degrees of freedom have been investigated. It is argued that in order to fully understand and appreciate the low temperature properties of the materials investigated such a coupling must be taken into account.

The work elucidates the novel physical and thermal properties of thin and ultra-thin films of crosslinked polymer and organized microstructures with a special emphasis on surface and interfacial effects and the structure-property relationships. Two major crosslinked polymer coatings have been thoroughly investigated: polymer microstructures fabricated by multi-laser interference lithography (IL), and plasma polymer coatings. We unveiled intriguing thermal properties of plasma polymer films originating from their physical state and exploiting the same for the design of ultrasensitve chemical sensors. A novel paradigm of surface coatings, single and bi-component periodic, porous crosslinked polymeric structures, has been introduced and thoroughly studied. Surface, interfacial, and mechanical properties of these novel class crosslinked polymer coatings clearly demonstrate the enormous potential of the IL microstructures as organized multicomponent polymer systems. When subjected to external or internal stresses the periodic porous structures can exhibit a sudden and dramatic pattern transformation resulting in remarkable change in the photonic, phononic and mechanical properties of these structures. Furthermore, the confinement of these instabilities to localized regions results in complex hierarchical structures. The two polymer coatings (plasma polymers and IL microstructures) with complementary attributes (such as periodic structure, vertical stratification, residual internal stresses, and high surface and interface tunability) enabled us to understand and design novel multifunctional polymer coatings.