Steels with complex microstructures such as tempered martensite often exhibit anisotropic (orientation dependent) mechanical properties. The hierarchical microstructure is composed of laths, blocks and packets with particular crystallographic orientation relationships inherited from prior austenite grains. Analysis with crystal plasticity methods reveals that martensite packets show quite anisotropic mechanical properties, whereas a complete prior austenite grain composed of several packets behaves rather isotropically. In the scope of this work, the mechanical properties of martensite packets and prior austenite grains are homogenized in order to employ them at macroscopic level. A computational method has been adopted in order to homogenize the microscopic stresses of a representative volume element (RVE) generated by multi-level Voronoi tessellations mimicking the hierarchical microstructure of martensite. These RVEs are mechanically loaded in different directions and the generated yield surfaces are fitted to a flow rule, which is then utilized for conventional continuum plasticity models. Additionally to providing the data basis for homogenization procedures, the mechanical behavior of the RVEs is analyzed to explore deformation heterogeneities in the microstructure, which lead to internal stresses from which cracks or other defects might originate.
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|Manuskript||This file contain the abstract of our proposed work. Please consider the sequence of authors based on this file. Hamad ul hassan will present the work but the first author is Rehman Hameed||28 KB||Download|