ORDER HARDENING IN NICKEL MOLYBDENUM AND NICKEL TUNGSTEN ALLOYS

Order hardening characteristics were studied in Ni-20% Mo, Ni-25% Mo and Ni-20% W. They were processed through quench and reheat cycles and the progress of order hardening was monitored through microhardness measurements. A correlation with the microstructure as observed with polarized light microscopy and transmission electron microscopy was established. Among the various factors, such as degree of order, domain size, coherency strains and dislocations, which can contribute to strengthening, domain size seems to play a major role.