رسالة جامعية
A theory-guided combinatorial materials design of ductile Mg-based alloys utilizing ab initio and atomistic methods
| العنوان: | A theory-guided combinatorial materials design of ductile Mg-based alloys utilizing ab initio and atomistic methods |
|---|---|
| المؤلفون: | Pei, Zongrui |
| المساهمون: | Raabe, Dierk, Svendsen, Bob, Neugebauer, Jörg |
| المصدر: | Aachen : Publikationsserver der RWTH Aachen University X, 123 S. : Ill., graph. Darst. (2015). = Aachen, Techn. Hochsch., Diss., 2015 |
| بيانات النشر: | Publikationsserver der RWTH Aachen University |
| سنة النشر: | 2015 |
| المجموعة: | RWTH Aachen University: RWTH Publications |
| مصطلحات موضوعية: | info:eu-repo/classification/ddc/620, Ingenieurwissenschaften, Mg alloys, ductility, ab intio methods, combinatorial materials design |
| جغرافية الموضوع: | DE |
| الوصف: | Energy savings and CO2 reductions are among the most essential tasks in materials science and engineering. Any successful attempt to achieve both goals requires the development of novel light-weight metallic materials. New Mg alloys play a key role owing to their combination of relatively high strength and low density. However, their wider use is hindered by their low room temperature ductility. Recent mechanical testing of pure bulk Mg and of a single phase solid solution Mg-3-wt.-%-Y performed at the Max-Planck-Institut für Eisenforschung (MPIE) in Düsseldorf, Germany, showed that the addition of yttrium increases the room temperature ductility about 5 times and lowers theso-called I1 intrinsic stacking fault (I1 SF) energy. In order to obtain a deeper insight into the mechanisms responsible for this increased ductility, the above described experimental studies have been complemented at MPIE by a quantum-mechanical study. Using density functional theory (DFT) calculations, Y additions were found to significantly reduce the I1 SF energy in excellent qualitative agreement with experiments.This thesis contains a thorough analysis of the above mentioned scale-bridging connection between atomic-scale reduction of I1 SF energies and an increased macroscopic ductility in Mg alloys. DFT calculations of I1 SF energies in 20 different binary Mg alloys have been performed but only rare-earth elements have been found to reduce theI1 SF energy and increase the ductility. This prediction was experimentally confirmed at MPIE in case of Mg-Tb, Mg-Dy, Mg-Ho, Mg-Er alloys that all turned out to be ductile. When designing new ductile Mg alloys, rare earth elements do not represent an optimum choice due to their limited natural resources and environmental concerns in their mining and production. In order to identify alternative solutes ductilizing Mg alloys, we have searched for relations between materials properties of elemental solutes and theirimpact on the I1 SF energies in Mg alloys. The atomic volume, the electronegativity ... |
| نوع الوثيقة: | doctoral or postdoctoral thesis |
| اللغة: | English |
| العلاقة: | info:eu-repo/semantics/altIdentifier/urn/urn:nbn:de:hbz:82-rwth-2015-043337; https://publications.rwth-aachen.de/record/481719Test; https://publications.rwth-aachen.de/search?p=id:%22RWTH-2015-04333%22Test |
| الإتاحة: | https://publications.rwth-aachen.de/record/481719Test https://publications.rwth-aachen.de/search?p=id:%22RWTH-2015-04333%22Test |
| حقوق: | info:eu-repo/semantics/openAccess |
| رقم الانضمام: | edsbas.CC895111 |
| قاعدة البيانات: | BASE |
| الوصف غير متاح. |