Aerospace and Automotive

Company

Jaguar Land Rover and University of Warwick

Challenge

Energy absorption is important for the safety of car passengers. Besides the seat foam used for comfort, modern vehicles have a denser foam such as expanded polypropylene (EPP) inside headrests and bumpers that decelerates passengers in such a way as to minimise any stresses on them. Ideally, a foam would do this by deforming in a controlled manner, reducing the maximum forces experienced by the occupant.

Solution

The researchers studied EPP’s energy-absorption properties under deformation at the ESRF, using new material models to improve a computer-aided design process. At the beamline ID19, the researchers performed microtomography, which enabled them to continually image their EPP foams (see figure above) as they were slowly compressed with a dedicated press facility. Incorporating the images into a three-dimensional computer model, the researchers could analyse them to understand how to improve the foam, and how much of it to use in a vehicle for optimal performance.

Benefit

The benefit of the ESRF in this research was the ability to track the deformation in situ an in great detail. “The facilities available at the ESRF will allow us to improve the use of polymer foams as energy absorbers in our vehicle range”, expalins Mark Blagdon, a materials engineer who led the project from Jaguar Land Rover. 

Company

University of Hamburg, University of Siegen, DESY, MAXIV

Challenge

Catalysts in a car contain noble metal nanoparticles consisting of rhodium, platinum and palladium and alloys thereof. These make the harmful molecules produced by the motor react on the surface of the converter while reaching high temperatures and reducing and oxidising atmospheres. When catalysts operate, the particle size of the noble metals increases. It is a process called sintering, which results in a decrease of the overall catalyst surface area. In the long run, this reduces the number of active sites from the surface and makes the catalyst less efficient.

Sample

The sample consisted of stripes of platinum-rhodium nanoparticles with varying composition from pure platinum to pure rhodium and a constant height.

Solution

Synchrotron radiation makes it possible to carry out operando experiments where scientists can monitor nanomaterials while the catalytic reaction takes place under realistic thermal and process conditions. The team used high-energy grazing incidence X-ray diffraction and online mass spectrometry.

Benefits

The experiments focused on the behaviour of the alloy nanoparticles during catalytic oxidation of carbon monoxide to carbon dioxide at a temperature of 550 K and near-atmospheric pressures. The results showed that platinum particles increase in height and lead to a reduction of the total particle surface coverage. This did not happen so much with the rhodium and rhodium-rich particles, which indicates that rhodium might be an important ingredient for catalyst stabilization.

Nature Communications, DOI: 10.1038/NCOMMS10964

Company

Vienna University of Technology (TU WIEN), German Aerospace Center (DLR)

Challenge

The transportation sector moves towards greater energy efficiency in all areas (i.e. from component production over to fuel consumption) in order to meet the latest performance and environmental targets. The success and progress fulfilling these goals is highly dependent on the availability of new engineering materials and manufacturing methods that enable significant weight savings associated with simultaneous improvements in component performance. Titanium alloys exhibit higher specific strength than other structural materials as well as excellent corrosion and creep resistance up to about 500 °C. These properties represent many performance advantages for the transportation industry. Despite these benefits and the relatively large resource reserves (titanium is the fourth most abundant metal in the earth’s crust), titanium alloys still come at high production costs that limit their industrial usage.

Titanium-based components are mainly produced via the classical process of ingot metallurgy (cast and wrought) which provides alloys with high strength levels. At this stage of manufacturing, thermal and thermo-mechanical treatments determine the microstructural characteristics, i.e. the mechanical properties of titanium alloys. On the other hand, selective laser melting (SLM) is a very promising powder-bed based “3D printing” technique that manufactures near net-shape metallic components with higher resource-efficiency than conventional fabrication methods. Consequently, considerable cost savings can be achieved. One of the main key strengths of SLM is that extremely complex geometries inaccessible using conventional manufacturing techniques can be manufactured. In this way, structures of minimal weight and optimized functional performance can be produced. However, the very fast cooling rates reached during solidification of molten metal pools during SLM produce brittle titanium based components with poor mechanical performance.

Monitoring the kinetical evolution of the microstructural phases of titanium based components during thermal and thermomechanical treatments would help scientists rationalize their processing either via ingot metallurgy or advanced SLM while improving their mechanical performance (e.g. strength and fatigue resistance).

Sample

The a+b Ti-6Al-4V and Ti-6Al-6V-2Sn as well as the metastable b Ti-10Al-2Fe-3Al, Ti-5Al-2Sn-2Zr-4Mo-4Cr, Ti-5Al-5Mo-5V-3Cr-1Zr titanium alloys presenting different initial microstructures.

Solution

The researchers carried out in situ high energy synchrotron X-ray diffraction experiments at the ID15B beamline. Image sequences of complete Debye–Scherrer rings from the bulk of the studied alloys were recorded in transmission mode while heating and cooling the sample within the same temperature ranges used in the industry. This allowed univocal determination of the phase transformations kinetics (i.e. the evolution of the volume fractions and lattice parameters of phases) which confine the microstructural changes of the alloys, i.e. their mechanical properties. Moreover, three-dimensional (3-D) imaging was performed at the ID22NI beamline by high-energy magnified synchrotron tomography using Kirkpatrick–Baez focusing optics, to analyse morphological features of the microstructure (e.g. non-uniform distribution of phases, formation of complex structures, or contiguity between them) and understand their relationship with the mechanical properties of the studied alloys.

Benefits

The studies provide an advance in the current knowledge of the phase transformation kinetics of titanium alloys mostly discussed in the basis of stable conditions (e.g. isothermal aging and ex-situ experiments). This will help to develop new theoretical models for microstructure prediction leading to improvements in functional alloy design, lead-time and cost savings via knowledge-based thermal treatment optimization. Particularly, the results obtained will contribute to overcome the present manufacturing restrictions of SLM manufacturing.

Journal of Materials Science 50, 1412-1426.  

a) Visualisation of fuel spray from an injection nozzle using synchrotron X-ray radiography at 2 Mfps and 0.5 µs exposure. b) Tomographic imaging of carbonaceous deposits inside the injector nozzles. Image credits: P. Hutchins, Prism Scientific Limited.

Legend. The 3D stacked memory modules studied at beamline ID09. Credits: ESRF/C. Argoud.