A numerical analysis of cold powder compaction based on micromechanical experiments

• Compaction of cemented carbide granules is studied using the discrete element method.
• The mechanical properties of the granules at low strains are given from a granule compression test.
• Granule properties at higher strains are investigated using nanoindentation testing.
• Contact force between two particles is computed using FEM.
• There is an excellent agreement between DEM and the presently made compaction experiments.

The discrete element method (DEM) is used for predicting the compaction behavior of two types of spray dried cemented carbide granules. The material model of the granules is determined by micromechanical experiments. First, compression tests are performed on single granules giving information of the deformation behavior at relatively small deformations. For larger deformations, nanoindentation tests are performed to give further information of the constitutive behavior indicating a strong hardening behavior at high strains. The material model is implemented in an FE model of two particles in contact and the relation between contact force and indentation depth is exported to a DEM program. The DEM program is used to simulate presently performed uniaxial die compaction experiments where the geometry of the die is taken into account. Excellent agreement is found between the experiments and the numerical predictions in the range where results from DEM simulations are valid.

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