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Key Application Areas• Increased future role for Mg in
transport (33% lighter than Al) • Future vehicle concepts assume
greatly increased application of Mg as part of multi-material structure
• Challenges• Making complex shapes using Mg• Reducing anisotropy/asymmetry of properties • Joining Mg to Al and steel, joining cast Mg alloys• Corrosion control (coatings/protection systems)
SuperLight CarMagnesium
Mg Research – Current Hot Topics• Based on a survey of recent conference
proceedings, top research areas for Mg are– Improving low temperature formability (texture
control, rare-earth additions etc.)– Alternative production routes (e.g. twin roll
casting, advanced casting processes)– Bio-resorbable magnesium alloys for implants– Corrosion control (alloy design and coatings)– Improving strengthening response (improving
precipitation hardening...)
International Picture• China, Germany, Canada, Australia and
US all have major Mg research activities• China
– National Engineering Research Centre for Magnesium Alloys, Chongqing ~80 academics
• Germany– Magnesium Innovation Centre (MagIC)
~50 scientists• Canada
– MagNET. 20 academics from 5 partner universities
UK Picture• UK Mg research activity is comparatively small
(handful of academics “part time” on Mg) but maintains wide coverage and internationally recognized position
• Mg research in UK receives ~ 5% of light metals funding
• Significant Mg activity within:– LATEST2 programme– Towards Affordable, Closed-Loop Recyclable Future
Low Carbon Vehicle Structures (TARF-LCV)– Centre for Innovative Manufacture in Liquid Metal
Engineering (LiME)– Doctoral Training Centre in Advanced Metallic
Systems (DTC)• Most UK Mg research involves collaboration with
industry - Magnesium Elektron
Reducing Temperature for Forming• Unlike steel/Al magnesium cannot be
formed at room temperature (hcp crystal structure)
• Reducing temperature required to form Mg is critical to economics for automotive sheet– Alloy design, e.g. dilute rare-earth
additions– Fundamental understanding of formability
in Mg– Alternative processes, e.g. superplastic
forming• Relevant UK research
– Alloy design and fundamentals [Manchester]
– Forming trials and alternative processes [Imperial/Warwick]
Improved formability with dilute rare-earth additions
Alternative Process Routes• Reducing cost of Mg requires using lower cost production route• Twin roll casting (TRC) attractive option
– Avoids need for large rolling reduction (difficult with Mg)– Potential to maintain randomized (cast) texture in sheet product– Potential to directly form TRC sheet (e.g. with superplastic forming)
• Research needed to improve consistency, microstructure and properties of TRC-Mg
• UK active through TRC optimization LiME [Brunel], microstructure and corrosion performance [Manchester]
TRC sheet Light further warm rolling
Warm forming
Direct superplastic forming of TRC sheet
Bio-resorbable Mg Alloys• Potential of Mg for bio-resorbable
implants has attracted massive new research interest in past ~10 years
• Magnesium Elektron developed Synermag – first commercial Mg alloy designed for biological applications
• UK research– Mg alloy optimization and biological
performance [Manchester]– Magnesium Elektron in-house
activities
Magnesium alloy stent
Corrosion Control and Coatings• Corrosion control is critical for Mg use• Mg corrosion is highly sensitive to impurities
(e.g. Fe)– Key concern for recyclability
• Mg corrodes rapidly in contact with other metals – must be electrically isolated
• UK research– Fundamentals of corrosion in Mg alloys
[Manchester]– Coating and protection systems for dissimilar
joints [Manchester]– Effect of recycling/impurities on corrosion
[Brunel, Manchester]Corrosion of ZE41 with PEO coating
[Manchester]
time
Improving Strengthening Response of Mg• Highest strength Mg alloys only ~ ½
strength of strongest Al alloy• Strongest Mg alloys are precipitation
hardened (as with Al)• Requires improving effectiveness of
precipitates in Mg to provide strength– Fundamentals of strengthening in
alloy systems that twin [Manchester]– New alloy systems– Micro-alloying to promote
precipitation (as in Al)– Computer based alloy design (ICME)
[Manchester]
Other Research Topics• Recent/ongoing UK research in
– Dissimilar metal joining of Mg to steel, Al structures [Manchester, Warwick]
– Magnesium based carbon reinforced composites [Manchester]
– Friction stir welding of magnesium [Manchester/Sheffield]
