Nanostructured bulk steels
Event details
| Date | 17.11.2014 |
| Hour | 13:15 › 14:15 |
| Speaker | Prof. Dierk Raabe, Max-Planck Institut für Eisenforschung, Düsseldorf, Germany |
| Location | |
| Category | Conferences - Seminars |
Developing strong, damage-tolerant, and functional steels shapes the backbone for industrial innovations in manufacturing, energy, transportation, and safety. Examples are Fe-Cr steels for emission-reduced turbines; weight reduced and ultra-high strength Fe-Mn-Al steels for light-weight and safe mobility; magnetic Fe-Si steels for low-loss electrical motors and generators; or stainless steels for power plants. These examples document the necessity of developing improved high strength and yet ductile steels. Most traditional hardening mechanisms, however, such as enabled by solutes, dislocations, or precipitates, albeit leading to high strength, often reduce ductility rendering the material brittle and susceptible for failure. This phenomenon is sometimes referred to as the inverse strength-ductility problem.
Reduction the grain size offers a pathway for increasing both, strength and toughness. Here we develop this concept further in that we combine this strategy with the manipulation of individual interfaces by grain boundary segregation and even local phase transformation. More specific, we enable grain boundaries in steels not only as barriers against dislocation motion but also as regions where segregation and nanoscale phase transformation occur. Such locally transformed regions can act as compliance layers impeding for instance crack penetration among lath martensite lamellae.
• Duarte MJ, Klemm J, Klemm SO, Mayrhofer KJJ, Stratmann M, Borodin S, Romero AH, Madinehei M, Crespo D, Serrano J, Gerstl SSA, Choi PP, Raabe D, & Renner FU, II. Element-Resolved Corrosion Analysis of Stainless-Type Glass-Forming Steels. Science 2013; 341: 372-376.
• Raabe D, Sandloebes S, Millan J, Ponge D, Assadi H, Herbig M, & Choi P-P. Segregation engineering enables nanoscale martensite to austenite phase transformation at grain boundaries: A pathway to ductile martensite. Acta Materialia 2013; 61: 6132-6152.
• Herbig M, Raabe D, Li Y, Choi P, Zaefferer S, Goto S, Atomic-Scale Quantification of Grain Boundary Segregation in Nanocrystalline Material, Phys Rev Letters 112, 126103 (2014)
Bio: Dierk Raabe holds Dipl-Ing. (summa cum laude) and Dr.-Ing. (summa cum laude) degrees in physical metallurgy and metal physics from RWTH Aachen. Currently he is Chief Executive of the Max-Planck Institut für Eisenforschung in Düsseldorf and Professor at RWTH Aachen University. His focus is in physical metallurgy and materials physics. Specifically he works on the simulation and mechanical properties of metallic alloys. He wrote and edited several books on this topic, e.g. ‘Computational Materials Science’ (1998), Continuum Scale Simulation of Engineering Materials’ (2005), and ‘Crystal Plasticity FEM in Materials Science and Engineering’ (2010) as well as more than 400 peer reviewed publications (more than 8500 cites, H-factor 49). Dierk Raabe is also active in transferring computational materials engineering into industrial practice.
Raabe’s work places emphasis on the comparison of simulations with novel experimental results conducted under complex boundary conditions. Currently, Raabe aims at the integration of quantum mechanical simulations into engineering materials design and property predictions. This changes computational materials science from a descriptive into a predictive method. A special feature of the approach is that atomistic simulations are combined with atomic scale characterization and the actual synthesis and processing of new alloys. The common vision of these activities is the use of predictive simulations and their consequent engineering application for inventing advanced alloys. The aim is the physically-based design of materials with superior properties (strength, elongation, damage tolerance) for the fields of energy, mobility and health from the atomic to the macro-scale under consideration of synthesis and processing. The blend of theory, characterization, and processing is important in Raabe’s work. He is a frequent plenary and keynote speaker. In 2004 he received the highest German research award (Leibniz-Award). 2008 Raabe was awarded Lee Hsun Lecture Award of the Institute of Metal Research of the Chinese Academy of Sciences and in 2011 the Weinberg Lecture Award of the University of British Columbia. In 2012 he received an ERC advanced grant. Raabe mentored more than 50 Ph.D.s, many of whom now hold leading positions in companies and academia as faculty members in the US, UK, and Asia. Since 2010 he is a member of the Science Advisory Board of the German Government. Since 2012 he is the chairman of the Governors Board of RWTH Aachen University. He is a member of the National Academy Leopoldina.
Reduction the grain size offers a pathway for increasing both, strength and toughness. Here we develop this concept further in that we combine this strategy with the manipulation of individual interfaces by grain boundary segregation and even local phase transformation. More specific, we enable grain boundaries in steels not only as barriers against dislocation motion but also as regions where segregation and nanoscale phase transformation occur. Such locally transformed regions can act as compliance layers impeding for instance crack penetration among lath martensite lamellae.
• Duarte MJ, Klemm J, Klemm SO, Mayrhofer KJJ, Stratmann M, Borodin S, Romero AH, Madinehei M, Crespo D, Serrano J, Gerstl SSA, Choi PP, Raabe D, & Renner FU, II. Element-Resolved Corrosion Analysis of Stainless-Type Glass-Forming Steels. Science 2013; 341: 372-376.
• Raabe D, Sandloebes S, Millan J, Ponge D, Assadi H, Herbig M, & Choi P-P. Segregation engineering enables nanoscale martensite to austenite phase transformation at grain boundaries: A pathway to ductile martensite. Acta Materialia 2013; 61: 6132-6152.
• Herbig M, Raabe D, Li Y, Choi P, Zaefferer S, Goto S, Atomic-Scale Quantification of Grain Boundary Segregation in Nanocrystalline Material, Phys Rev Letters 112, 126103 (2014)
Bio: Dierk Raabe holds Dipl-Ing. (summa cum laude) and Dr.-Ing. (summa cum laude) degrees in physical metallurgy and metal physics from RWTH Aachen. Currently he is Chief Executive of the Max-Planck Institut für Eisenforschung in Düsseldorf and Professor at RWTH Aachen University. His focus is in physical metallurgy and materials physics. Specifically he works on the simulation and mechanical properties of metallic alloys. He wrote and edited several books on this topic, e.g. ‘Computational Materials Science’ (1998), Continuum Scale Simulation of Engineering Materials’ (2005), and ‘Crystal Plasticity FEM in Materials Science and Engineering’ (2010) as well as more than 400 peer reviewed publications (more than 8500 cites, H-factor 49). Dierk Raabe is also active in transferring computational materials engineering into industrial practice.
Raabe’s work places emphasis on the comparison of simulations with novel experimental results conducted under complex boundary conditions. Currently, Raabe aims at the integration of quantum mechanical simulations into engineering materials design and property predictions. This changes computational materials science from a descriptive into a predictive method. A special feature of the approach is that atomistic simulations are combined with atomic scale characterization and the actual synthesis and processing of new alloys. The common vision of these activities is the use of predictive simulations and their consequent engineering application for inventing advanced alloys. The aim is the physically-based design of materials with superior properties (strength, elongation, damage tolerance) for the fields of energy, mobility and health from the atomic to the macro-scale under consideration of synthesis and processing. The blend of theory, characterization, and processing is important in Raabe’s work. He is a frequent plenary and keynote speaker. In 2004 he received the highest German research award (Leibniz-Award). 2008 Raabe was awarded Lee Hsun Lecture Award of the Institute of Metal Research of the Chinese Academy of Sciences and in 2011 the Weinberg Lecture Award of the University of British Columbia. In 2012 he received an ERC advanced grant. Raabe mentored more than 50 Ph.D.s, many of whom now hold leading positions in companies and academia as faculty members in the US, UK, and Asia. Since 2010 he is a member of the Science Advisory Board of the German Government. Since 2012 he is the chairman of the Governors Board of RWTH Aachen University. He is a member of the National Academy Leopoldina.
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Practical information
- General public
- Free
Organizer
- Holger Frauenrath
Contact
- Holger Frauenrath