IJMC/FEF Student Research Competition

Abstract A method to produce ductile iron with a novel austenite plus martensite microstructure has been discovered by combining an appropriate chemistry of manganese, nickel, and carbon, with an appropriate heat treatment. Various austenitizing temperatures and times were used to change the amount of carbon in solution as well as how far the carbon diffused from the graphite nodules and as-cast carbides. Upon cooling, the final microstructure is high-carbon martensite plus chemically stabilized austenite that is directly correlated to the heat treatment procedure. The microstructural array creates a variation in mechanical properties between those of fully martensitic and fully austenitic ductile irons. The mechanical properties can be altered by tempering the high-carbon martensite.