Microstructure characterization of Mg Castings for Ductility Prediction
EMSL Project ID
47721
Abstract
Mg castings have found increasing applications in lightweight vehicles because magnesium and its alloys are the lightest metallic structure materials. However, a critical technical hurdle hindering the wider applications of Mg castings in vehicle applications is its limited ductility. It is well known that the intrinsic/extrinsic microstructural features can have the influence on the ductility of Mg casting materials. Especially, the extrinsic defects such as the porosity can be the dominant ductility limiting factor for locations with porosity volume fraction exceeding a critical value. As the ductility of Mg castings can be governed by the local pore distribution features rather than overall distribution features, exact characterization of 3D microstructure/pore distribution in Mg castings is crucial in the accurate prediction of their ductility. The objective of this work is to use the X-ray tomography to characterize 3D microstructure of porous Mg alloys made from high pressure die casting (HPDC). Some tensile samples, cut out of Mg casting plates, will first be scanned to obtain the X-ray tomography data. The obtained tomography data will be processed with the image processing tool, which is currently under development in our group, in order to visualize 3D pore distributions within the sample. Characterization of pore distribution features will then be performed based on the 3D pore visualization for the whole sample as well as for the small-sized local regions throughout the sample. Comparison between the local pore distribution features and the ductility of the corresponding samples is expected to provide the clues for the widely scattered ductility of Mg casting. The obtained 3D pore visualization can also be used to generate the actual microstructure-based finite element (FE) models. When the FE results are validated against the tests, synthetic microstructure-based models considering various pore distribution features can be generated and simulated to investigate their effects on the ductility of Mg casting materials.
Project Details
Start Date
2012-11-05
End Date
2013-10-30
Status
Closed
Released Data Link
Team
Principal Investigator
Co-Investigator(s)
Team Members
Related Publications
Choi KS, Z Zhu, X Sun, E De Moor, MD Taylor, J Speer, and DK Matlock. 2015. "Determination of carbon distributions in quenched and partitioned microstructures using nanoscale secondary ion mass spectroscopy." Scripta Materialia 104:79-82. doi:10.1016/j.scriptamat.2015.03.027
Oudriss A, S Le Guernic, Z Wang, B Osman Hock, J Bouhattate, E Conforto, Z Zhu, D Li, and X Feaugas. 2015. "Meso-scale anisotropic hydrogen segregation near grain-boundaries in polycrystalline nickel characterized by EBSD/SIMS." Materials Letters. doi:10.1016/j.matlet.2015.12.016