INFLUENCE OF SMALL VANADIUM AND COBALT ADDITIONS ON MICROSTRUCTURE AND PROPERTIES OF DUCTILE IRON

Ductile irons containing additions of up to 0.44%V and 0.48%Co have be en prepared and tested in the as cast state and after a ferritising he at treatment. In the heat treated condition the microstructure of the alloyed irons consists of graphite nodules in a ferrite matrix that co ntains a fine dispersion (20-80 nm in dia.) of V4C3 particles. These c arbide particles produce dispersion strengthening and refine the grain size of the ferrite, resulting in an iron of intermediate strength an d high ductility. (C) 1995 The Institute of Materials.