GP Multiscale Computational Methods for Designing Multimodal Materials
Jinghong Fan (Alfred University), ross Stewart (Alfred University)
Computational Materials Design via Multi-scale Modeling
Wed 10:45 - 12:15
Barus-Holley 190
Most of the existing material-strengthening methods result in deteriorated tensile ductility. Achieving simultaneously high strength and high ductility in metals and alloys has hence emerged as an essentially challenging issue in the application of nanostructured metals/alloys. In recent years, some approaches of microstructure design for developing metals and alloys with simultaneously high strength and high ductility have been proposed, for example by designing multimodal materials by mixing coarse grains of micrometer size in the nanostructured materials. Whilst the development is encouraging the underlying mechanisms is not quite clear and the approach doesn’t involve optimum quantification. This will require a lot of trial and error over a long time to get design information. This work uses the multiscale analysis of the GP method, short for generalized particle dynamics, to carry on the analysis for bimodal copper and aluminum oxide. This presentation will describe how we solve several key issues of using atomistic-based multi-scale modeling for bimodal material design which include how we can extend the grain size from nanometers to micrometers, which are necessary for simulation and development of the bimodal material and how we can explore and characterize defects quantitatively in atomistic/nanoscopic scales where failure originates. The former is solved by the GP dual scale concepts of atom lumping and particle decomposition and the equivalence principle of constitutive laws between different scales of the same material elements with the same microstructure. The latter is treated by the introduction of a new concept, method and variable for defect nucleation and evolution and then they are linked to the global stress-strain behavior of material. Having the capability to include m grains in the GP model, the interrelationships between defects at lower scales such as GBs and global stress-strain curve at several critical points can be analyzed.