BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Memento EPFL// BEGIN:VEVENT SUMMARY:IMX Seminar Series - Grain Boundaries: An “old” Defect Gaining New Momentum in Materials Science DTSTART:20230327T131500 DTEND:20230327T141500 DTSTAMP:20260528T011505Z UID:946d4d3502b00a3e5c23eea93f812e3712874d1f1a448613706d374d CATEGORIES:Conferences - Seminars DESCRIPTION:Prof. Gerhard Dehm\, Max-Planck-Institut für Eisenforschung G mbH\, Düssedlorf Germany\nGrain boundaries (GBs) are omnipresent in most materials and often decisive for the resulting material properties. Electr ical resistivity in metals increases by the additional scattering of elect rons at GBs\, while for ceramic varistors the electrical activity of GBs l eads to highly non-linear electrical conductivity. Many metals fail by seg regation induced embrittlement of GBs – examples are S in Ni or Zn in Fe . However\, GB segregation may also “stabilize” nanocrystalline metals by reducing GB energy (and often also kinetics) to prevent spontaneous gr ain growth\, which leads to high strength materials due to the numerous GB s acting as obstacles for dislocation motion.\nRecently\, it has been reso lved that GB can undergo structural transitions triggered by temperature\, pressure and chemical composition\, and thus properties may alter as a fu nction of these variables. In ceramics like alpha Al2O3 it is debated if s uch transitions are the cause of abnormal grain growth. In the present tal k newest results obtained by atomic resolved transmission electron microsc opy for metallic materials are provided\, shedding light on the GB phase t ransitions also termed “complexion” transitions in literature to discr iminate it from bulk phases. Examples include Al and Cu in pure and alloye d form as well as Fe based materials with multiple alloying additions. Tec hniques to address material properties for single GBs are briefly discusse d.\nBio: Gerhard Dehm is director at the Max-Planck-Institut für Eisenfor schung in Düsseldorf and professor at the Ruhr-Universität-Bochum. From 2005 to 2012 he was head of the department Materials Physics at the Montan universität Leoben (Austria)\, and managing director of the Erich Schmid Institute of the Austrian Academy of Sciences. His research focusses on ad vanced S/TEM and in-situ microscopy of interfaces\, their structure\, chem istry\, stability\, and impact on material properties. This research direc tions was recently awarded with an ERC Advanced Grant. A further cornersto ne of his research is small scale mechanical testing to provide fundamenta l understanding of local mechanical properties of materials. LOCATION:https://epfl.zoom.us/j/63993722592 STATUS:CONFIRMED END:VEVENT END:VCALENDAR