Ductile and High Strength White Cast Iron of Ultrafine Interconnected Network Morphology

Abstract

Fe100–x C x melts (x = 18 to 24) can be cast under B2O3 flux into solids of interconnected network morphology, with a wavelength in the submicron range. There are two major constituent subnetworks, which are a brittle Fe3C subnetwork and a ductile αFe subnetwork. The Fe100–x C x network alloys, therefore, are white cast iron of novel microstructure. Fe100–x C x specimens of x = 18 to 21 are ductile and the yield strength can be as large as ~3200 MPa. Fe100–x C x specimens of x = 22 to 24 are in the regime of a ductile-to-brittle transition. The compressive strength is high, at ~2700 MPa. Microstructural analysis indicates that the ultrafine network morphology and the ductile αFe subnetwork are responsible for the ductility exhibited in Fe100–x C x network alloys of x = 17 to 21. They are also responsible for the high compressive strength in Fe100–x C x network alloys of x = 22 to 24.