Finite Element Study of Intragrain Plastic Heterogeneity near a Triple Junction
- PDF / 1,030,746 Bytes
- 9 Pages / 593.972 x 792 pts Page_size
- 66 Downloads / 135 Views
INTRODUCTION
INSIDE a polycrystalline microstructure, the distribution of strain is heterogeneous in nature. Grains that are favorably oriented with regard to external loading tend to deform more than others. This intrinsically results in differences in the strain fields at the intergrain level. Grains interact with each other to ensure stress equilibrium at grain boundaries while respecting geometric compatibility. Such interactions may result in the fragmentation of grains and the formation of new boundaries.[1–3] Understanding of both intra- and intergrain strain heterogeneity is an important issue in the area of polycrystal plasticity modeling. Statistical models aimed at predicting deformation textures and plastic anisotropy perform much better when mesoscale strain heterogeneity is accounted for.[4–6] However, the modeling sometimes relies on simplistic assumptions. For example, in the advanced LAMEL model, a plastically deforming grain is assumed to be subdivided into several zones of influence that interact exclusively across one grain boundary.[7] Currently, the model does this subdivision in a purely heuristic fashion, since there is no clear physical understanding as to how this happens in real materials. Experimental studies related to grain interaction and subdivision mostly rely on the microstructural analysis of the already deformed polycrystals. More specifically, the developments of regions of different crystallographic orientations (subdivision/fragmentation) within a grain ANAND KRISHNA KANJARLA, formerly Doctoral Student, Department of Metallurgy and Materials Engineering, K.U. Leuven, BE-3001 Leuven, Belgium, is Postdoctoral Researcher, Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87544. Contact e-mail: [email protected] LAURENT DELANNAY, Professor, is with the Department of Mechanical Engineering (Cesame-MEMA), Universite´ catholique de Louvain (UCL), BE-1348 Louvain-la-Neuve, Belgium. PAUL VAN HOUTTE, Professor, is with the Department of Metallurgy and Materials Engineering, K.U. Leuven. Manuscript submitted December 12, 2009. Article published online October 19, 2010 660—VOLUME 42A, MARCH 2011
are studied using either transmission electron microscopy[8] or electron backscattered diffraction[9,10] analysis. However, very little is known about the factors leading to the fragmentation of grains in the first place. To study those factors, one would need to follow the evolution of local strain fields. Experimentally, this is difficult to do. In the few cases where it is attempted, only partial strain information is available and that, mostly from the surface. Performing joint experimental and numerical simulations would yield better insight in understanding the local heterogeneity. Efforts in this direction can be broadly classified as either (1) local orientation measurement based or (2) surface strain measurements based. Combining experiments and crystal plasticity finite element method (CPFEM), Kalidindi et al.,[11] Erieau and Rey,[12] Raabe et al.,[13] and Delan
Data Loading...
