The Effect of Carbon and Silicon Alloying Additions on the Morphology of Pores and Tensile Characteristics of Sintered Steels

Abstract

The influence of C and Si on pore morphology and tensile behavior of Fe–C–P–Si was investigated. The contribution of C on the morphology of pores was explained using thermodynamic formulation by incorporating the surface curvature effect. Thermodynamic analysis of the pore surface suggests that C is enriched at all regions within the pore whether its convex or concave regions, resulting in C coverage of the surface pore. The C coverage will reduce the surface energy without changing the pore’s morphology. Accordingly, C has no effect on surface rounding of pores. Compacted tensile test specimens of Fe–C–P–Si powder were made to produce elongated pores. Tensile testing shows the effect of the sintered density, microstructure, pore morphology, and grain boundary on the mechanical properties. It was found that ductility is affected by pore morphology and grain boundaries, but UTS is more affected by the sintered density and the matrix microstructure.