Quantitative image analysis in some iron powder metallurgy materials

Abstract

The goal of the present paper is to analyze the porosity in some powder metallurgy (P/M) alloys by two different methods, using the conventional method and by image processing analysis method. Quantitative image processing is a new and useful tool which is able to determine the pore size, pore size distribution and porosity of parts obtained by P/M route. One important and significant disadvantage of P/M processing is the presence of porosity due to their activity as crack initiators and due to their presence as the stress distribution in compacts is nonhomogeneous in the cross-section. Two atomized iron powders obtained by powder metallurgy with particles of different sizes (< 45, 45-63, 63-100, 100-150, >150 µm) are the based materials studied in this paper. The analyzed powders were subjected to uniaxial pressing with 500 MPa as the applied pressure. The compacts disc dimensions obtained are ϕ 8 × 6 mm in dimensions. The compacts were sintered in a laboratory furnace at a temperature of 1.120 °C. The sintering time was 60 and 90 minutes. The sintered specimens obtained were analyzed regarding their density, microstructure and porosity. Porosity of iron-based P/M materials was measured using the conventional and image processing technique. A correlation between the experimental and software data analysis could be established.