Click on the speaker below for their abstract details:
Prof. Dr.-Ing Horst E. Friedrich;
Next Generation Car’s requirements, constraints and potentials for Magnesium lightweight concepts with integrated functions
German Aerospace Center (DLR), Institute of Vehicle Concepts, Stuttgart, Germany
Future automotive vehicles have to fulfil many aspects like energy saving or safety, economic and production targets. New vehicle concepts with electric drivetrains or autonomous drive for people movers, passenger or goods cars will change the paradigms of mobility.
With respect to this, weight saving remains being a must and Magnesium solutions could show even more potentials: casted structures with integrated functions, peeling mode mechanisms or foam filled profiles are examples developed and demonstrated in DLR’s metaproject for Next Generation Car (NGC). Mg extrusions with polyurethane core show up to 3 times better specific energy absorption compared to hollow DC04 steel. Light and cost attractive Mg structures are shown with integrated A-pillar demonstrators, bringing together 20 single parts within one big casting that provides the advantage of 50% weight reduction. Challenges like modularisation strategy and life cycle assessment have to be met.
For green house gas emissions over the whole life cycle our comparison gives evidence that different Mg production routes determine the final result and that modern electrolysis processes or biomass based energy in production is advantageous even compared to an aluminium reference.
An overview about optimized a/o new applications will be discussed and shown.
Prof. Alan A. Luo;
Solidification and Precipitation Kinetics in Magnesium Alloys
The Ohio State University, Ohio, USA
While the thermodynamics and phase equilibria for magnesium alloys have been relatively well understood due to the intensive research in the last decades, the lack of kinetic models and experimental research has hindered the fast and efficient development of new magnesium alloys and the optimization of existing magnesium alloys and manufacturing processes. In this talk, non-equilibrium solidification and precipitation kinetics of Mg-Al and Mg-Al-Sn systems are modelled. The micromodel for solidification during high pressure die casting includes the effect of back diffusion in the solid phases. The precipitation model is based on the classical Kampmann-Wagner numerical (KWN) model, which allows modelling the process of concurrent nucleation, growth and coarsening. Non-spherical/non-cuboidal precipitates in magnesium alloys can be studied by assuming shape-preserved growth of the precipitates. These models are integrated to predict the yield strengths of magnesium alloys both in as-cast and heat-treated conditions. The modelling results are validated by experiments.
Prof. Jianfeng Nie;
Lattice Defects, Solute Segregation and Precipitation in Mg Alloys
Department of Materials Science and Engineering, Monash University, Victoria, Australia
Significant progress has been made since 2000 in the understanding of lattice defects (dislocations, stacking faults, deformation twins), solute segregation and precipitation in magnesium alloys and their impact on deformation behaviour, formability and mechanical properties. This progress is achieved through the use of advanced experimental techniques and integrated computational materials engineering. Despite this achievement, there are still some controversial views and unresolved issues on the identities of lattice defects and structures of precipitates in some magnesium alloys of technological or commercial significance. This presentation will provide a review of our recent findings in the study of dislocations, stacking faults, deformation twins, solute segregation and precipitation in a group of magnesium alloys using atomic-resolution Z-contrast high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and energy-dispersive X-ray spectroscopy (EDS-STEM), together with first-principles density functional theory computations and phase field simulations.
Dr David Klaumünzer;
New Magnesium Alloys for Automotive Applications
Volkswagen AG, Group Research, Materials and Manufacturing Processes, Wolfsburg, Germany
Volkswagen shares a long history of using magnesium for vehicle components. Early applications date back to the Volkswagen Beetle which even to today’s standards can be considered a magnesium intensive vehicle. In fact, with 42,000 t annually, Volkswagen was Europe´s largest magnesium consumer in 1971. Today, applications are limited to a small number of castings in the drive-train, interior or very rarely car-body. In order to enhance the use of magnesium in future vehicles and unveil the full potential of magnesium as a lightweight material, its application spectrum needs to be extended to include sheet components. However, by simple comparison to aluminium and steels it becomes apparent that the property spectrum of magnesium sheets remains narrow and requires substantial broadening by fundamental alloy development. For economic reasons, we employ twin-roll casting (TRC) as the processing method of choice and use a step-wise upscaling approach. Thus we can show that a new alloy within the Mg-Zn-Ca-Zr system can be processed up to 1400 mm in width at an industrial scale and results in a beneficial combination of strength and formability. The improved formability stems from a texture weakening effect. It can be shown that such a new alloy sheet can be formed successfully into prototype components at reduced temperatures, thus contributing to a more viable and economic production of magnesium components.
Dr Zisheng Zhen;
Magnesium material supply issues and opportunities
Magontec Xian Co. Ltd, Germany
Magnesium material has been continuously considered and believed as promising light weight material in various application areas for decades. However in reality the actual application and consumption of magnesium alloys is far behind the expectation. Although there are reasons such as relatively immature development on both materials and processing techniques, issues on material supplying aspect like supply reliability, sustainability, environmental performance, material flow etc. have also significant impact. This presentation will provide an overview on those issues from a magnesium supplier perspective and then an update on the latest development toward new solutions and improvements. The latest development will bring new chances on facilitating Mg application expansion toward a new era.
Prof. David H. StJohn;
Grain Refinement of Magnesium: what we thought we knew 20 years ago, what we think we know now, and what do we need to know in the future?
The University of Queensland, School of Mechanical and Mining Engineering, St Lucia, Queensland, Australia
The last 20 years have seen significant advances in our understanding of the mechanisms of grain refinement, prediction of grain size, optimisation of refinement by zirconium, enhanced nucleation by external fields such as melt conditioning and ultrasonic treatment, and more recently the introduction of nanoparticles. We look back at what we thought we understood about the grain refinement of magnesium and its alloys 20 years ago and then what we understand today. Finally, we look forward to what we need to know as there are still significant challenges in implementing a commercially viable and reliable grain refining technology for Mg-Al based alloys. Based on the knowledge that has been created we speculate on what can be done to overcome these challenges in order to obtain the best refinement outcomes during the casting of a range of magnesium alloys.
Dr. Jon T. Carter;
Challenges and Opportunities for Implementing Magnesium in Automotive Applications
GM Global R&D Center, Warren, MI 48090
Future fuel economy pressures are driving the need for vehicle weight reduction. Magnesium being the lightest structural metal has a great opportunity to contribute to overall lightweighting, however, several challenges that remain: cost, large thin wall castings, corrosion mitigation with mixed materials, plasticity, and performance in the final sub-system. This talk will highlight current R&D being done to address these challenges, including alloy and process development, fundamental corrosion studies related to microstructure, and multi-scale plasticity modeling.
Prof. Mikhail L. Zheludkevich;
Novel approaches for active corrosion protection of Mg alloys
MagIC-Magnesium Innovation Centre, Helmholtz-Zentrum Geesthacht, Geesthacht, Germany
Magnesium and its alloys are among the lightest structural metallic materials. However the high corrosion susceptibility significantly limits their application range. Design of Mg alloys with a stable and dense oxide/hydroxide layer and with a uniform microstructure, which does not create strong internal micro-galvanic couples, can partially improve the situation. When such alloy is used in a less aggressive environment it can stay reasonably passive. However it is well known that another important factor, namely noble impurities present in the Mg-based materials, can play detrimental role for corrosion resistance. Proper surface pre-treatment and cleaning technologies can reduce the surface contamination level, though additional high barrier coatings should be applied in order to ensure acceptable resistance of Mg alloys for structural applications.
An additional complementary approach is to introduce the corrosion inhibitors in to the protection scheme. The corrosion inhibitors locally leached from the damaged layer can actively suppress the corrosion rate in the defects increasing the fault-tolerance of the protective coatings.
In the present work the new approaches for inhibition of Mg corrosion as well as the new active protective coatings will be discussed.
Prof. Kazuhiro Hono;
From age-hardenable magnesium alloys to bake-hardenable magnesium alloys
National Institute for Materials Science, Tsukuba 305-0047, Japan
Since the age-hardening responses of magnesium alloys without rare earth elements are poor, precipitation hardening has not been used in conventional wrought magnesium alloys. However, microalloying often leads to substantial improvement of age-hardening responses, and high yield strength over 370 MPa was reported for peak-aged Mg-Sn-Zn-Al alloy. In general, yield strength has a trade-off relationship with formability in magnesium alloys, so there is no high-strength magnesium alloys with excellent room temperature formability. In order to achieve both high strength and excellent room temperature formability, we have developed age-hardenable alloys, i.e., solution treated (T4) alloys in general have low yield strength; hence, they can show good formability if texture is weakened; using improved age-hardening responses in compositionally optimized magnesium alloys, the yield strength of formed sheets can be enhanced by artificial aging. In this talk, we review the development of age-hardenable wrought magnesium alloys including Mg-Zn-Al, Mg-Al-Ca and Mg-Sn-Zn-Al systems, all of which use only ubiquitous elements. To reduce the processing cost, we have developed dilute alloys that can be extruded or rolled at high processing rates. The Mg-1.3Al-0.3Ca-0.4Mn (wt.%) alloy that we developed recently can be extruded at high die-exit speed of 24 m/min and it can be age-hardened by the precipitation of Guinier-Preston zones. The peak aged AXM10304 exhibited yield stress of 288 MPa and elongation of 21 %, which are superior to those of 6000 series aluminum alloys. One of the alloys we have developed, Mg-1.2Al-0.8Zn-0.5Ca-0.4Mn (wt.%) alloy, shows excellent room temperature formability with index Erichsen value of 7.7 mm and a high yield strength over 200 MPa after T6 treatment. The time to reach the peak-hardness is less than 1 h at 170C, that is paint bake-hardenable. The systematic investigations toward the development of such bake-hardenable magnesium sheet alloy will be presented.
Prof Liming Peng;
Fatigue behaviour and additive manufacturing of Mg rare-earth alloys
National Engineering Research Center of Light Alloy Net Forming and State Key Laboratory of Metal Matrix Composite, Shanghai Jiao Tong University, Shanghai, P.R. China
Fatigue performance of Magnesium alloys is very important for their actual applications in the industries, however, there is lack of systemic research on the fatigue properties and mechanism of Magnesium alloys, especially those newly-developed Mg-Rare earth (RE) based ones. Herein, the researches on fatigue properties and behaviours of Mg-RE alloys at Shanghai Jiao Tong University were reported. High cycle fatigue properties of several kinds of Mg-RE alloys fabricated by different processes were tested and statistical prediction models of HCF strength and life were established based on testing parameters as well as key microstructural constituents. Furthermore, laser scanning confocal microscopy (LSCM), electron back-scattered diffraction (EBSD) and digital image correlation (DIC) were applied to the study of surface morphology variation of Mg-RE alloys before and after fatigue deformation, in order to explore their fatigue failure mechanism. Two kinds of typical damage morphologies were observed in fatigued Mg-RE alloy: One was parallel lines on basal planes led by the accumulation of basal slips, called persistent slip markings (PSMs), and the other was lens shaped, thicker and in less density, led by the formation of twinning. The surface fatigue damage morphology evolution was analyzed in a statistical way. The influences of stress amplitude and grain orientation on fatigue deformation mechanisms were discussed and the non-uniform deformation among grains and the PSMs, within twinning were described quantitatively. In general, fatigue crack initiation and failure of Mg alloys mainly come from the macro-and/or-micro structural non-uniformity of components formed during their manufacturing(AM). Therefore, we have tried to use additive manufacturing process to make Mg samples for the purpose of more uniform macro-and-micro structure. Our preliminary research results of AM of a Mg-RE alloy were introduced in the final of report. A microstructure of extremely fine equiaxed grains (2 μm) and secondary phases as well as weak textures were got by SLS process. Compared with conventional cast-T6 alloy (288 MPa), SLM-T5 alloy has much higher yield strength (385 MPa), which are even higher than extruded-T5 alloy with same chemical composition.
Prof. Kwang Sean Shin;
Research and Development Status of Magnesium Alloys in Korea
Professor and Director - Magnesium Technology Innovation Center, School of Materials and Science Engineering, Seoul National University, Korea
Magnesium alloys are the lightest structural metals, and have good physical and mechanical properties that make them extremely attractive for applications requiring lightweight materials. The global market for magnesium alloys has steadily expanded in the past decade, stimulated by the strong demand from the automobile and electronic industries for lightweight magnesium components. In order to meet the demand of new high performance alloys and overcome technical challenges, there has been active research at universities, national research institutes and industries to develop new magnesium alloys and processing technologies in Korea. This lecture will introduce the major magnesium R&D activities and recent research highlights in Korea.
Prof. Fusheng Pan;
Recent development of magnesium alloys and their processing technologies in China
Prof. Qing Liu;