THE STRUCTURE OF M_2C IN HIGN Co-Ni ALLOY STEEL

摘要

The high Co-Ni ultrahigh strength steel(UHS) is notable for the magnificent combination of high strength and toughness. In recent microstructure studies of secondary hardening behavior in AM 100 steel; shows that the secondary hardening is accomplished by the precipitation of fine-scale M_2C alloy carbides. But the structure of the fine precipitating carbides could not be unambiguously determined by Atom probe(AP) and transmission electron microscopy(TEM). In the present work, the precipitates are observed directly at high resolution electron microscopy (HRTEM), the carbide crystal structure and its orientation with matrix were also determined.