Browsing Monographs and Chapters in Monographs /TS by Issue Date

Now showing items 1-20 of 26

Carbon/carbon, cement, and ceramic matrix composites

Warren, Richard; Malmö University. School of Technology : Oxford
Comprehensive composite materials;4 (2000) BOOK
Den svenskaste historien: nationalism i Sverige under sex sekler

Hall, Patrik : Carlsson Bokförlag (2000) BOOK

Kulturgeografi - en ämnesteoretisk introduktion

Gren, M; Hallin, Per Olof : Liber (2003) BOOK
Diskursanalys av nationell identitet

Hall, Patrik
Book chapter in Identitetsstudier i praktiken : Liber (2003) BOOK CHAPTER
Miljö som politik

Jamison, Andrew : Studentlitteratur (2003) BOOK

Modelling of Fracture Processes During Fast Crack Growth

Ståhle, Per
Book chapter in Crack Dynamics
Advances in fracture mechanics;9 (2004) BOOK CHAPTER

The microstructures of Ti-6Al-4V and Ti-6Al-2Sn-4Zr-6Mo and their rel...
Pederson, Robert : Luleå tekniska Universitet (2004)	DOCTORAL THESIS

English abstract:

The research described in the thesis concerns phase transformations and mechanical properties of the titanium alloys Ti-6Al-4V and Ti-6Al-2Sn-4Zr-6Mo. The need to weld the alloys for certain engine components can expose the alloy locally to non-optimum thermal cycles and it is therefore of importance to gain an understanding of the kinetics involved in the phase transformations during heating and cooling. Moreover, for the purpose of modelling and computer simulations of heat treatments and welding processes, quantitative descriptions of the transformation are necessary. One focus in this work has been to examine the feasibility of using high temperature X-ray diffraction (HT-XRD) to study the phase transformation kinetics. Another aim in this work was to develop a weld simulation model leading to a prediction of the joint structure and microstructure of an electron beam welded component of the alloy Ti-6Al-4V. Electron beam welding (EBW) and friction welding (FRW) of Ti-6Al-4V and Ti-6Al-2Sn-4Zr- 6Mo have also been investigated, including microstructural weld characterization and the effect of post weld heat treatments on selected mechanical properties. In addition, two components of Ti-6Al-4V produced by ring-rolling and closed die forging, respectively, showed unexpected differences in low cycle fatigue (LCF) under certain loading conditions. Quantitative metallographic studies and texture examinations were conducted in order to find possibly reasons for the observed difference in fatigue properties. The HT-XRD technique was successfully used to monitor the alpha-to-beta transition during heating and the beta-to-alpha transition during cooling and including the transformation kinetics during isothermal hold. From the recorded spectra the thermal expansion properties for the alpha and beta phases could be extracted up to a temperature of 1050C, enabling the determination of the overall thermal expansion for the alloy by using rule of mixture (ROM) calculations. The weld simulation model here presented proved to predict the joint structure and microstructure of an electron beam welded Ti64 component with reasonable good accuracy, both in terms of thermal history during welding and also in terms of martensitic fraction formed during cooling and the distribution of martensite through the cross section of the FZ and HAZ. All mechanically tested Ti64/Ti6246 EBWs and FRWs, independent of PWHT temperature, fractured in the Ti64 base material and not in the weld region, thus, both types of welding processes seem to be promising candidate methods for successful joining of the Ti64 alloy to the Ti6246 alloy. Quantitative metallographic studies revealed that the closed die forged material exhibited a finer primary alpha grain size and a finer Widmanstätten platelet colony size which would be expected to provide a superior resistance to fatigue crack initiation. Observed differences in the texture of the two materials as determined by electron back-scattered diffraction might also have contributed to the difference in fatigue properties.

Aspects of Precipitation in Alloy Inconel 718
Azadian, Saied : Luleå Tekniska Universitet (2004)	DOCTORAL THESIS

English abstract:

A study was made of the microstructure of the Ni-base alloy Inconel 718 with emphasis on the precipitation and stability of intermetallic phases as affected by heat treatments. In addition the effect of the precipitation on selected mechanical properties namely hardness, creep notch sensitivity and hot ductlity were investigated. The materials studied were a spray-formed version and three wrought versions of the alloy. The spray-formed version of the alloy was of interest since it exhibited a superior compositional homogeneity to more conventional forms of the alloy. To characterise the precipitation kinetics and to determine the associated hardening, a series of isothermal ageing treatments were carried out on both spray-formed and ring rolled material at selected temperatures between 600°C and 1025°C for up to 100h. The results were presented in the form of TTH diagrams for the two alloys. The heat treated specimens were then studied using optical microscopy, scanning electron microscopy and transmission electron microscopy. Where possible these were supplemented with quantitative metallographic measurements of volume fraction and precipitates size.The three main intermetallic precipitation phases in IN 718 are (i) gamma’ having a composition Ni3(Al,Ti), a cubic crystal structure and cubic or spherical particle shape (ii) gamma” having a composition Ni3Nb, a bct crystal structure and a lens-like disc shape (iii)delta having composition Ni3Nb, an orthorhombic crystal structure and forming as grain boundary particles and films as well as thin plates extending long distances into the grains. In thermomechanically processed material the delta-phase can also occur as shorter platelets and particles resulting from fragmentation of the original plates. In this work the rates of precipitation and the temperature ranges of their existence were determined qualitatively. Moreover the coarsening of the ganmma" precipitates was determined quantitatively. The kinetics of precipitation and dimensional coarsening of the delta-phase were also established quantitatively. Similarly, the dissolution kinetics of the delta-phase were measured in the spray-formed and three wrought versions of the alloy leading to a determination of the effect of Nb-content on the delta solvus temperature. After a standard heat treatment, the spray-formed IN 718 was found to be creep notch sensitive according to an SAE-AMS standard rupture test. It was found that notch ductility could be restored to the alloy by inserting a delta-phase precipitation treatment at 875°C-900°C prior to the standard heat treatment. This could be attributed to the formation of a more favourable delta-phase morphology than that formed during the solution treatment at 954°C in the standard heat treatment cycle. A study was made of high temperature tensile properties of a wrought version of IN 718 in particular in relation to the problem of hot cracking in repair welding. Measurements were made of the strength loss temperature on heating and the strength and ductility return temperatures on cooling. These properties provide an indication of the sensitivity of the alloy to hot cracking due to liquation. The tests were made on the alloy after various heat treatments designed to produce microstructures with two different grain sizes with and without delta-phase precipitation. Hot tensile tests were also performed on the in-situ solidified alloy in order to describe the weld metal ductility and properties. The grain size and the presence of large fractions of delta-phase precipitated at 900°C had only small effects on the strength loss temperature and brittle-ductile transition of the alloy. On the other hand, a small fraction of delta-phase precipitated in the grain boundaries at 960°C reduced the brittle-ductile transition temperature significantly. It is proposed that the reduction was associated with interaction between the grain boundary delta-phase and grain boundary boron segregation that was observed in all the heat treated materials.

Weakening of Crack-tip Singularity due to Buckling of Thin Bodies und...

Li, Cong : Lund University (2007) LICENTIATE
THESIS

e-Läranderesurser i Sverige
Amhag, Lisbeth; Nilsson, Bengt J Book chapter in Från didaktik till e-didaktik (2010)	BOOK CHAPTER

English abstract:	We give a brief history of distance learning in Sweden. We then present the main electronically available resources that have been established in recent years for learning purposes. We divide the resources into two categories: Administrative resources. These include LMS-systems and other systems to administer applications, student result, course material, etc. We present studera.nu which is the Swedish application website for all university courses and programs, Ladok and Skola24, the student result databases for universities and schools, nationwide. Educational resources. These are mainly web-based systems containing material that can be used for education. We present LIBRIS Uppsök and SwePub, the two Swedish National Libary websites containing all theses and essays published at Swedish universities. We also look at the electronic library search system for Malmö University as an example of an online library system. Finally, we discuss internationally available resources such as Wikipedia, Google search and Google scholar as well as the educational aspects of social networking systems such as Facebook, Myspace and Classroom 2.0.
Swedish abstract:	Vi ger en kort översikt över distansundervisningens historia i Sverige. Vi presenterar sedan de vanligaste digitala resurserna som etablerats under senare år för utbildningsändamål. Vi delar dessa resurser i i två kategorier: Administrativa resurser. Dessa inkluderar LMS-system och andra system för administration av ansökan, registrering, studieresultat, kursmaterial, m.m. Vi presenterar studera.nu som är den svenska webbplatsen för ansökan till alla högre studier, Ladok och Skola24, de två resultatdatabaserna som används för registrering av studieresultat vid skola och högre utbildning över hela landet. Undervisningsresurser. Dessa är i huvudsak webb-baserade system innehållande material som kan användas i utbildning. Vi presenterar LIBRIS Uppsök och SwePub, Kungliga bibliotekets två databaser innehållande alla uppsatser och avhandlingar publicerade vid Svenska universitet. Vi tittar också på elektroniska bibliotekssystemet vid Malmö högskola som ett exempel på ett modernt digitalt bibliotekssystem. Slutligen diskuterar vi internationellt tillgängliga resurser som Wikipedia, Google Search och Google Scholar såväl som utbildningsaspekterna av sociala nätverkssystem som Facebook, MySpace och Classroom 2.0.

H-T - BOK - Bes ... Svenska Upplagan - Sve.pdf (2.304Mb)

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Carbon/carbon, cement, and ceramic matrix composites
Warren, Richard; Malmö University. School of Technology : Oxford Comprehensive composite materials;4 (2000)	BOOK

Den svenskaste historien: nationalism i Sverige under sex sekler
Hall, Patrik : Carlsson Bokförlag (2000)	BOOK

Particle and whisker reinforced brittle matrix composites
Hansson, T; Warren, Richard Book chapter in Carbon/Carbon, Cement, and Ceramic Matrix Composites Comprehensive Composite Materials;4 (2000)	BOOK CHAPTER

Boundary blow-up insemilinear elliptic problems with singular weights...
Cheng, Yuanji Book chapter in Applicable Mathematics : its perspectives and challenges : Narosa publishing house, New Delhi (2001)	BOOK CHAPTER