Date | Time
19/06/2017 | 14 h 00 min - 18 h 00 min
Arts et Métier ParisTech
“The role of grain boundary structure and hydrogen on interfacial fracture toughness”
All grain boundaries are not equal in their predisposition for fracture due to the complex coupling between lattice geometry, interfacial structure, and mechanical properties. The ability to understand these relationships is crucial to engineer materials resilient to grain boundary fracture.
In this presentation, I will present a methodology to isolate the influence of grain boundary structure on the tensile strength and work of separation of grain boundaries using atomistic simulations. Instead of constructing sets of grain boundary models by simply varying the misorientation angle around a fixed misorientation axis, the proposed method creates sets of grain boundary models by means of isocurves associated with important lattice properties. Such properties may include the elastic modulus normal to the grain boundary, the Schmid factor for primary slip, and the propensity for simultaneous slip on multiple slip systems. This approach eliminates the effect of lattice properties from the comparative analysis and thus enables the identification of structure-property relationships for grain boundaries.
As an example, I will illustrate this methodology to study intergranular hydrogen embrittlement. Segregated H emphasizes differences in the selected grain boundary structures.
*Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.