TY - JOUR A1 - Baer, Wolfram T1 - Advanced fracture mechanics testing of DCI - A key to valuable toughness data N2 - The challenge of how to adequately characterize the toughness behavior of ductile cast iron (DCI) materials had been solved through the development and application of fracture mechanics concepts. Outstanding examples are found in the design and safety assessment procedures of sophisticated DCI components for wind turbines or transport and storage casks for radioactive materials. An essential requirement for these procedures is to have adequate fracture mechanics toughness data available. Because DCI materials may substantially change their deformation, damage and fracture behavior from ductile to brittle by increasing loading rate, decreasing temperature, increasing pearlite share and increasing stress triaxiality, the corresponding experimental measuring techniques and analysis concepts have to be chosen and adapted with deliberation. Long-time experience in this field is imperative to provide valuable data. BAM has been dealing with mechanical and fracture mechanical characterization of DCI materials for more than 30 years. This paper demonstrates state-of-the-art fracture mechanics test methods for the determination of quasi-static and dynamic fracture toughness. Among others, it is exemplarily shown for a variety of DCI materials conforming to grade EN-GJS-400 how mechanical and fracture mechanical properties are influenced by temperature, loading rate and microstructure. A major lesson to be learned is that fracture toughness data of DCI should always be discussed, reported and used in correlation with microstructural parameters. KW - DCI KW - Ductile cast iron KW - Mechanical properties KW - Fracture mechanics testing KW - Fracture toughness data KW - Microstructure KW - Loading rate KW - Temperature PY - 2014 SN - 1939-5981 VL - 8 IS - 2 SP - 25 EP - 34 PB - AFS CY - Schaumburg, Ill. AN - OPUS4-30755 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Baer, Wolfram T1 - Performance of modern DCI materials - Investigation of microstructural, temperature and loading rate effects on mechanical and fracture mechanical properties N2 - Design and safety assessment of advanced ductile cast iron (DCI) components like wind turbines or transport and storage casks for radioactive materials require appropriate material data in terms of strength and fracture toughness. Therefore, it is of vital importance to characterize and understand the deformation, damage and fracture behaviour of DCI which may substantially change from ductile to brittle by increasing loading rate, decreasing temperature and/or increasing stress triaxiality. This paper reports on recent BAM inverstigations on different qualities of the widely used DCI grade EN-GJS-400 with varying pearlite shares (none and 18% respectively). The focus was on the influences of microstructure, temperature (ambient and -40 °C) and loading rate (quasi-static to crash) on strength (YS, UTS, flow curve) and fracture mechanical properties (R-curve, crack initiation toughness, fracture toughness). Systematic metallographical and fractographical analyses were performed accompanying the whole test program and a systematics of specific damage behaviour and fracture mechanisms was derived from the results. T2 - THERMEC' 2013 CY - Las Vegas, USA DA - 02.12.2013 KW - Ductile cast iron KW - Microstructure KW - Pearlite KW - Temperature KW - Loading rate KW - Damage behavior KW - Mechanical properties KW - Fracture toughness KW - Fracture mechanics KW - Ductility KW - Damage KW - DCI PY - 2014 U6 - https://doi.org/10.4028/www.scientific.net/MSF.783-786.2244 SN - 0255-5476 VL - 783-786 SP - 2244 EP - 2249 PB - Trans Tech Publications CY - Aedermannsdorf, Switzerland AN - OPUS4-30643 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -