We are pleased to announce a monograph "DISCRETE ELEMENT MODELING OF POWDER METALLURGY PROCESSES", by Szymon Nosewicz (IPPT Reports 5/2016). The doctoral dissertation presents a numerical and experimental analysis of manufacturing of new materials by powder metallurgy techniques. The scope of the thesis includes three main parts:

  • formulation of an original numerical model of powder metallurgy,
  • simulations of hot pressing for different combinations of process parameters,
  • verification of the numerical model based on own experimental results.

The main part of the doctoral dissertation is dedicated to the theoretical and numerical investigations. An original numerical model of a powder metallurgy process has been formulated and implemented within the discrete element framework. The proposed model allows to study the motion (shrinkage and rearrangement) of powder particles during compaction and sintering stage and takes into account the growth of cohesive necks. In order to verify, calibrate and validate the numerical model, several simulations of hot pressing and sintering process have been performed. Numerical results have shown the correct representation of the density, shrinkage and densification rate of sintered specimens for different combination of process parameters. Validation of numerical model has been brought by performance of own experimental studies, which refers to manufacture the intermetallic NiAl, ceramic Al2O3 and NiAl-Al2O3 composite specimens and characterization of its mechanical and microstructural properties. Further numerical studies have comprised evaluation of micro- and macroscopic stresses during and after powder metallurgy process.

The results presented in this thesis have shown that the developed original discrete element model is an effective and suitable tool to analysis phenomenon occurring during the powder metallurgy process. Numerical model allows to study the material mechanism both at microscopic (such as a rearrangement and interaction of powder particles) and macroscopic scale (such as shrinkage, material densification or macroscopic stress). Presented results allow to the conclude that the new discrete element model can be applied to development and optimization of powder metallurgy processes.