High Strength Magnesium Alloy AZ31 Composites with Ca Additions and Nano Alumina Dispersions: Processing Technology, Microstructural Control and Property Evaluation

Project: Research

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Description

In view of their light weight, magnesium materials are being increasingly sought after for structural applications in aerospace, automobile, computer hardware and more recently for bio-degradable implants. Among the many wrought magnesium alloys developed, Mg-3Al- 1Zn (AZ31) is most extensively studied over the past decade. However, this alloy has some limitations when it comes to creep strength, microstructural inhomogeneity and strength level compared to other light alloys. In addition, processing and conversion to wrought condition is a major challenge in magnesium materials in view of their low workability and pose different challenges depending on the system. In this project, it is proposed to address these three issues with the object of developing and processing AZ31 based high strength magnesium composites for structural applications. Firstly, it is proposed to alloy AZ31 with Ca so that stable intermetallic particles like (Mg,Al)2Ca are produced in the matrix to impart high temperature creep strength. Secondly, higher level of strengthening will be achieved by dispersing nano-alumina particles which decorate and strengthen the prior particle boundaries in the alloy. In both these steps, it is necessary to find optimum levels of Ca as well as nanoalumina to achieve higher strength levels without seriously reducing the ductility. The alloys and composites will be prepared by disintegrated melt deposition (DMD) technique followed by hot extrusion. Finally, it is proposed to develop the complete processing technology for hot working of these newer materials using dynamic materials modeling technique with emphasis on microstructural control and workability optimization. For this purpose, the techniques of processing maps and kinetic analysis will be applied for workability optimization and for evaluation of hot working mechanisms, respectively. Hot compression tests will be conducted to generate the experimental data necessary for applying these materials models. The results will be validated using detailed microstructural examination of deformed specimens. The outcome of this project is the synthesis of a new high strength magnesium alloy nano composite which can be hot worked into components with consistent microstructures and mechanical properties on a repeatable basis in a manufacturing environment. In addition, mechanical properties at application temperatures will also be evaluated so that they can be compared with the performance of competing materials.

Detail(s)

Project number9041667
Grant typeGRF
StatusFinished
Effective start/end date1/01/1221/06/16