|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Fundamental Aspects and Modeling Powder Metal Synthesis and Processing
||Anisotropy of Mass Transfer during Sintering of Powder Materials with Pore-Grain Structure Orientation
||Diletta Giuntini, Elisa Torresani, Chaoyi Zhu, Tyler Harrington, Kenneth Vecchio, Alberto Molinari, Eugene Olevsky
|On-Site Speaker (Planned)
A micromechanical model for shrinkage anisotropy during sintering of metallic powders is proposed and experimentally assessed. The studied powder samples are pre-shaped into their green forms by uniaxial cold pressing before the sintering routine. The samples therefore provide for a directional porous structure and inhomogeneous plastic deformation at the inter-particle contacts. These non-uniformities are considered to be the cause of anisotropic dislocation pipe diffusion, and thus the root cause of the undesired shape distortion during shrinkage. The proposed model describes the shrinkage rates in the compaction and transversal directions, as functions of both structural and geometrical activities of the samples. Dislocation densities can be estimated from such equations, along with dilatometry and image analysis data. The reliability and applicability of this modeling framework is validated by comparing the calculated dislocation densities with nanoindentation data and electron backscattered diffraction based geometrically-necessary dislocation density determinations.