Numerical Simulation of Refractory Metals and Cemented Carbides in the Regime of Powder Filling and Powder Transfer
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Proceeding on Plansee Seminar 2013
Die filling as an important part of the powder compaction in a powder metallurgical manufacturing route for refractory metals and cemented carbides is facing growing interest in the field of numerical process simulation. This is mainly because numerical models allow to study the mechanics of paritculate materials in greater detail than currently available measurements methods are being able within an industrial environment. In particular, spatial gradients in filling density and formation of free surfaces of the powder body in the as-filled condition are on the way being evaluated quantitatively by numerical models this way allowing to combine the corresponding simulation results with those obtained via already developed numerical models for the subsequent powder compaction and sintering process steps. As a primary advantage of such a combined modeling approach functional dependencies can be derived between process and material parameters of the die filling process and the resulting characteristics of the component in the as-pressed and as-sintered state. On the basis of the discrete element method, model parameter extraction, calibration, and validation is shown for a specific chromium based alloy. The applicability of the model is shown for a die filling process of an interconnector plate. Additionally, die filling is analysed numerically for a ready-to-press cemented carbide powder. In both cases, primary attention is being paid to the particle dynamics during die filling and formation of powder beds in the as-filled conditions. Evaluations of the relative filling density distributions will be addressed in upcoming investigations.