DMA
Deformation and plastification mechanisms in multiaxially loaded textured magnesium alloy

This fundamental research project, funded by the Austrian Science Fund (FWF) under project number I-4782, will determine the relationship between microstructural deformation mechanisms and macroscopic yield and fatigue behaviour of textured magnesium (AZ31B alloy) subjected to complex multiaxial stress states through carefully designed and implemented mechanical tests and state-of-the-art microstructural analysis. It will significantly enhance our understanding of magnesium and the capability of modelling current industrial magnesium alloys as well as newly developed magnesium alloys.

The premise of the project is to carry out uniaxial compression and pure shear testing of magnesium samples in-situ in a scanning electron microscope and to make real-time lattice orientation maps of grains within the sample, and to carry out biaxial compression tests of magnesium not in-situ and examine microstructural changes in the samples. These complex experiments require advanced instrumentation and the development of specialised equipment to make them possible.

The project is a DACH collaboration between the Centre for Lightweight Design (LLK) at the University of Applied Sciences, Landshut, Germany and the Department of Chemistry and Physics of Materials at PLUS. Work packages for the project include both scientific and technological components. Scientific co-workers at Landshut are Professors Otto Huber and Holger Saage and Mr. Anton Nischler, who are responsible for the mechanical testing aspects of the project, while at PLUS Dr. Lawrence Whitmore is responsible for the microstructural analysis.

Analytical studies include metalographic and microscopy studies of the magnesium samples utilising optical microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and lattice orienatation mapping using electron backscatter diffraction (EBSD).

Technological developments include the design and fabrication of various complex pieces of equipment including: a biaxial extensometer, an anti-buckling guide, a vibrational polisihng machine, a core drilling machine and various other components.

Due to disruptions and delays arising from the coronavirus lockdowns, the work schedule has been rearranged and additional items expanded to include innovation utilising 3D printing technologies.

More information on the research of Dr. Lawrence Whitmore can be found here: www.plus.ac.at/chemie-und-physik-der-materialien/staff-2/u-bis-z/whitmore

Progress to-date:

First biaxial compression tests have been made.

The biaxial extensometer is finished and tested.

In-situ pure shear tests have been made and are now completed.

In-situ uniaixal compression tests have been made and are finished.

The Kammrath&Weiss in-situ mechanical testing stage has been installed at the LLK.

A manual grinding tool has been developed for preparing magnesium samples. This was designed using a CAD software and constructed using a 3D printer. The design and some initial results have been published in the journal Ultramicroscopy.

A core drilling machine has been developed for preparing magnesium samples. The design and results have been published in Ultramicroscopy.

A vibrational polishing machine has also been developed for preparing magnesium samples for EBSD studies. This has also been published in Ultramicroscopy.

A new method of prearing EBSD samples from magnesium has been developed and was presented at the 11th Landshüter Colloquium on lightweight materials. This method utilising deionised water and absolute ethanol prepares magnesium surfaces without the formation of hydroxide and increases manifold the quality of EBSD maps possible on magnesium.

Dissemination of results:

Virtual presentation at the LightMat23 conference in Trondheim, Norway (21-23 June, 2023).

Oral presentation at the World Congress for Advanced Materials Science 2023, Barcelona (27-28 March, 2023).

Oral presentation at the 11th Landshüter Colloquium in Landshut, Germany (1-2 March 2023).

Oral presentation at the 71st Annual Meeting of the Austrian Physical Society ÖPG, Leoben (26-30 September 2022).

Two oral presentations have been given internally to colleagues in the Department of Physics and the Department of Chemistry and Physics of Materisls (CPM) at PLUS.

Publications:

L. Whitmore, Sustainable science through a case study of sample preparation using 3D printed tools, (2023) European Journal of Sustainable Development, Volume 12, No 4.

L. Whitmore, A precision dimple grinder-polisher produced by 3D printing, (2023) Ultramicroscopy, 113813, Doi:10.1016/j.ultramic.2023.113813.

L. Whitmore, A. Nischler, O. Huber, Preparation of magnesium AZ31B for electron backscatter diffraction (EBSD) analysis. (2023) In: Huber, O., Bicker, M., Patzelt, P. [Hrsg.]: 11. Landshuter Leichtbau-Colloquium, LC-Verlag, Landshut, März 2023, ISBN: 978-3-9818439-7-2.

L. Whitmore, A mini vibrational polishing machine produced by 3D printing, (2023) Ultramicroscopy 243, 113630, Doi: 10.1016/j.ultramic.2022.113630.

L. Whitmore, A precision manual grinding tool for sample preparation, (2022) Ultramicroscopy, 233, Doi: 10.1016/j.ultramic.2021.113436 113436.

L. Whitmore, A precision core drill for transmission electron microscopy samplepreparation produced by 3D printing, (2022) Ultramicroscopy, 241, Doi: 10.1016/j.ultramic.2022.113613.

In-situ uniaxial compression testing of magnesium AZ31B samples from the DMA project

Technological innovations from the DMA project

Microstructural analysis using innovative tools from the DMA project

Below is a video of the 3D printed core drill cutting a sample from a thin strip of magnesium

Below is a video of the 3D printed dimpler machine grinding a dimple in a magnesium sample