|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||Late News Posters
||PP-47: Towards Engineering the Electronic Structure of Lightweight Structural Alloys
||Deep Choudhuri, Srinivassan G Srivilliputhur, Mark A Gibson, Rajarshi Banerjee
|On-Site Speaker (Planned)
Electronic structures in metallic alloys play a crucial role in determining their structure and mechanical properties. Using Titanium and Magnesium alloys as examples we demonstrated that electronic structures could be engineered to selectively stabilize / de-stabilize precipitate phases and, improve mechanical behavior. For this purpose, phase formation and high temperature mechanical response of these alloys was examined by coupling detailed ab-inito calculations with experimental results. In metastable beta Ti alloys, embrittling omega phase is stabilized via anisotropic delocalization of valence electrons – a signature of covalency – between Ti and solute atoms. Increase in the solute content destabilizes the omega phase due to transition from covalent to metallic bonding. In contrast, Zn induced covalent bonding in Mg-rare earth alloys has a beneficial effect. Such bonding resulted in the formation of a new strengthening precipitate phase in high number densities, and prevented vacancy migration required for dislocation climb during creep deformation.