Ab initio and finite element simulations of material properties in multiphase ceramics [Elektronische Ressource] / vorgelegt von Maria Iuga

Ab Initio and Finite ElementSimulations of Material Propertiesin Multiphase CeramicsDissertation zur Erlangungdes naturwissenschaftlichen Doktorgradesder Bayrischen Julius-Maximilians-Universit¨at Wu¨rzburgvorgelegt vonMaria IugaWu¨rzburg 2007Eingereicht am ........................bei der Fakult¨at fu¨r Chemie und Pharmazie1. Gutachter: ........................2. Gutachter: ........................der Dissertation1. Pru¨fer: ........................2. Pru¨fer: ........................des ¨offentlichen PromotionskolloquiumsTag des ¨offentlichen Promotionskolloquiums:..........Doktorurkunde ausgeh¨andigt am: ..........AbstractIn the present study numerical methods are employed within the framework ofmultiscale modeling. Quantum mechanics and finite element method simulations havebeen used in order to calculate thermoelastic properties of ceramics. At the atomicscale, elastic constants of ten different ceramics (Al O , α- and β-SiC, TiO -rutile2 3 2and anatase, AlN, BN, CaF , TiB , ZrO ) were calculated from the first principles2 2 2(ab-initio) using the densityfunctional theory with the general gradient approximation.The simulated elastic moduli were compared with measured values. These results haveshown that the ab-initio computations can be used independently from experiment topredict elastic behavior and can provide a basis for the modeling of structural andelastic properties of more complex composite ceramics.