Charakterisierung von Eisenbasis-Sinterwerkstoffen durch quantitative Fraktographie / Characterization of Pressed and Sintered Ferrous Materials by Quantitative Fractography

From low-deformation fracture surfaces obtained by impact loading at 77K or by high cycle fatigue testing, the load bearing cross section can be quantitatively determined both for sintered iron and high strength steel, respectively. In the sintered iron, the fracture mode - cleavage fracture vs. ductile rupture ― also gives indication of the pore connectivity. In the technically interesting porosity range 5 to 20 % sintered iron can be imagined as containing both interconnected and isolated pores which are respectively grouped in clusters. Slight changes in total porosity or the sintering regime change the ratio of isolated to interconnected pores and thus strongly affect the load bearing cross section which in turn influences in particular the mechanical properties of the material