Search

The effect of pore drag on grain growth is one of the most frequent effects encountered in the last stage of sintering. Therefore, the understanding of the effect of microstructure and pore location, pore morphology on grain growth is essential. Here a migrating grain boundary interacts with pores and other grain boundaries such that its structure and energy vary during grain growth. Consequently, it is of great interest to see whether the grain boundary energy decreases or increases during the interaction between migrating grain boundaries and pores. In this paper, the conditions for grain boundary migration and pinning are related to pore curvature and illustrated theoretically and experimentally. [ABSTRACT FROM AUTHOR]

This study characterizes the sintering behavior of iron-base powder mixtures based on the alloy system Fe-P-C-Cu-Si. It is shown that the chemical composition and sintering conditions can be tailored to obtain a grey iron microstructure with a relative sintered density up to 95% of the pore free level. The approach is based on thermodynamic simulation and controlled sintering experiments with loose powder and die-compacted powder, including liquid forming additives. Attendant mechanical properties include an elongation to fracture ∼ 3%, and an ultimate tensile strength in the range 300-400 MPa. [ABSTRACT FROM AUTHOR]

The contribution of the surface active element Phosphorus (P) in pore rounding in sintered steels is absent in popular sintering models. Instead, these mathematical models analyze the rate of mass transport, which, according to these models, is driven by chemical potential gradients set up by the differences in the curvature of the free surfaces of the compact of contacting particles. To elucidate the effect that P has on rounding of pores in sintering models, an attempt has been made to incorporate surface curvature in Gibbs' surface thermodynamics. Using the image analysis method, a comparative study of pore morphology of sintered Iron-Carbon-Phosphorus (Fe-C-P) has been performed to study the effect P has on pore morphology. The application of the shape factor has been used to characterize the morphology of the pores. It was found that morphological enrichment and depletion of P are related to surface stresses as well as to the influence of vacancies. [ABSTRACT FROM AUTHOR]