BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Memento EPFL// BEGIN:VEVENT SUMMARY:IMX Colloquium - Ultrahigh-purified lean magnesium alloys for bior esorbable implant applications DTSTART:20250929T131500 DTEND:20250929T141500 DTSTAMP:20260921T202815Z UID:d0271dc46c82db5d03cb51458a3c09f46963266ceb846107c71afe30 CATEGORIES:Conferences - Seminars DESCRIPTION:Prof. Jörg F. Löffler\, Department of Materials\, ETHZ\, Swi tzerland\n\nTemporary medical implants that can be resorbed after fracture healing are beneficial for patients and necessary in certain clinical app lications. Magnesium-based implants are among the most frequently studied due to their unique properties. However\, they often comprise significant amounts of alloying elements to improve their mechanical properties. One w ell-known example is WE43\, which contains large amounts of rare-earth ele ments (about 4 wt.% Y and 3 wt.% Nd). In contrast\, we developed in recent years rare-earth free\, lean Mg alloys with alloying contents below 1 at. %\, also in ultrahigh-purified (XHP) versions with less than 5 ppm impurit y content [1]. This development generated alloys such as ZX10 (MgZn1.0Ca0. 3\, in wt.% = MgZn0.37Ca0.18\, in at.%) [2] and ZX00 (Mg0.45Zn0.45Ca) [3]\ , and other more recent lean Mg–Ca alloys (XHP X0) with alloying content s of less than 0.2 at.% [4]. Via optimized hot-extrusion processing we are now able to tune their microstructure and related properties\, generating high-strength alloys with a yield strength of >400 MPa at extended ductil ity (strong-X0)\, or >35% ductile alloys at intermediate strength (ductile -X0). \n\n \n\nIn this way we produced plate-screw implants for large-an imal tests\, where the plates were made of XHP ductile-X0 for adjustments to the bone shape and the screws were produced from XHP strong-X0. The X0 implants were inserted onto the pelvic bones of six adult female Swiss alp ine sheep and compared with WE43 [5]. CT and histological studies revea led an optimal average degradation rate of 0.3 – 0.4 mm/year for both me dical alloys. The bone-implant contact\, however\, was found to be signifi cantly higher for X0 than for WE43\, revealing a much better osseointegrat ion for the X0 implants. An analysis of the degradation products after exp lantation revealed further that rare-earth containing submicron particles remained embedded within the corrosion products of WE43\, while X0 underwe nt complete biodegradation. This shows that XHP lean Mg–Ca alloys presen t a new class of absorbable bone implants\, combining slow degradation\, e nhanced biocompatibility\, and strong mechanical properties. In fact\, imp lants based on ZX00 and X0 received already FDA approval (Bioretec) or an FDA “Breakthrough Device Designation” (ETH Spinoff\, Kairos Medical). This research may also generate a paradigm shift towards lean high-strengt h\, highly ductile (L-HS-HD) alloys\, where chemically simple materials ca n contribute to sustainable and more efficient materials recycling [6]. \ n\n \n\n[1] C. Wegmann et al.\, “Simultaneous distillation and alloying ”\, WO 2021/165139 A1. \n\n[2] M. Cihova et al.\, ‘Biocorrosion zoome d in: evidence for dealloying of intermetallic nanoparticles in Mg alloys ’\, Adv. Mater. 31\, 1903080 (2019). doi.org/10.1002/adma.201903080 \n\ n[3] T. Akhmetshina et al.\, ‘Quantitative imaging of magnesium biodegra dation by 3D X-ray ptychography and electron microscopy’\, Adv. Funct. M ater. 34\, 2408869 (2024). doi.org/10.1002/adfm.202408869 \n\n[4] T. Akhm etshina et al.\, ‘High-performance ultra-lean biodegradable Mg–Ca allo ys and guidelines for their processing’\, Acta Mater. 278\, 120247 (2024 ). doi.org/10.1016/j.actamat.2024.120247 \n\n[5] L. Berger et al.\, ‘In vivo performance of lean bioabsorbable Mg–Ca alloy X0 and comparison to WE43’\, Bioact. Mater. 44 (2025) 501 – 515. doi.org/10.1016/j.bioactm at.2024.09.036 \n\n[6] J. Plummer\, ‘Chemically-simple magnesium alloys for biomedical applications’\, Commun. Mater. 5\, 175 (2024). doi.org/1 0.1038/s43246-024-00613-1 \n\n\nBio: Jörg F. Löffler has been Professor at the Department of Materials\, ETH Zurich\, since July 2003. Starting a s Assistant Professor\, in 2007 he was elected Full Professor of Metal Phy sics and Technology. He currently serves as Chairman of the Department of Materials (2025 – 2027)\, resuming office after a first term in 2010 – 2013.\nBorn in Germany in 1969\, Jörg Löffler studied Physics and Mater ials Science at Saarland University. He then transferred to the Paul Scher rer Institute and ETH Zurich\, where he earned his doctorate in the magnet ism of nanostructured materials and neutron scattering (1997). Löffler th en took up a post at the California Institute of Technology as an Alexande r von Humboldt Fellow\, where he worked with Prof. William L. Johnson in t he area of bulk metallic glasses. In 2001 he was appointed tenure-track As sistant Professor at the University of California\, Davis\, where he staye d until his appointment to ETH Zurich in 2003.\nThe principal areas of Jö rg Löffler’s research are the synthesis and characterization of novel n anostructured and amorphous materials\; magnetic\, structural\, and thermo physical properties on the nanoscale\; the use of metals for medical appli cations (in particular bioresorbable implants)\; and neutron scattering an d synchrotron radiation. LOCATION:MXF 1 https://plan.epfl.ch/?room==MXF%201 STATUS:CONFIRMED END:VEVENT END:VCALENDAR