Micro-Mechanical Characterization of Magnesium Alloys
EMSL Project ID
42497
Abstract
The goal of this proposal is to understand the effects of various microstructural features on the deformation and strengthening mechanisms in magnesium alloys. It being the lightest structural metal, magnesium holds great promise for improved automotive fuel economy and reduced green-house gas emissions by enabling production of lighter vehicles. It is estimated that mass reduction of 70-75% can be achieved by replacing ferrous components in a car by an equivalent volume of magnesium components. Indeed, US DOE, as well as auto-industry world-wide, is investing significantly in understanding the fundamental deformation behavior of magnesium alloys. Magnesium can be strengthened through the addition of alloying elements that, in solid-solution and as precipitates, can influence the deformation mechanisms such as dislocation motion, twinning and grain-boundary sliding, as well as influence grain-growth at high temperatures. However, much needs to be learned with regards to the relative strengthening efficiencies of various microstructural features. Therefore, the key objective of this proposal is to determine the relative contribution of individual microstructural features to the overall mechanical performance. Traditional bulk-specimen testing can only provide an average mechanical response that, in itself, does not identify the role of individual microstructural features. Therefore, there is a need for an ability to interrogate the local micro-mechanical behavior in materials. EMSL's Dual-beam focused ion beam (FIB)-scanning electron microscopy (SEM) is an excellent tool that can enable specimen fabrication at specific locations within a microstructure. This ability will be used to micro-machine micro-pillar compression specimens at specific microstructural features such as precipitates, precipitate-free-zone, twin boundaries, grain boundaries etc. These micro-pillar compression specimens will be tested in a nano-indenter to determine their individual deformation behavior. Finally, the relative strengthening efficiencies of the microstructural features will be determined by comparing the local micro-mechanical behavior with the bulk specimen behavior. It is anticipated that this research will help design better magnesium alloys and assist US DOE in achieving its goal of 50% weight reduction in automobiles.
Project Details
Project type
Exploratory Research
Start Date
2011-02-01
End Date
2012-02-05
Status
Closed
Released Data Link
Team
Principal Investigator
Related Publications
Williams JJ, J Walters, M Wang, N Chawla, and A Rohatgi. 2013. "Extracting Constitutive Stress-Strain Behavior of Microscopic Phases by Micropillar Compression." JOM. The Journal of the Minerals, Metals and Materials Society 65(2):226-233. doi:10.1007/s11837-012-0516-9