Effect of Resolution Treatment on Impact toughness of Martensite in Fe - 18% Ni Alloy
이규복K . B . Lee, 안행근H . K . Ahn
Abstract
The effect of resolution treatment on the impact toughness of martensite in Fe-18%Ni alloy have been studied. The solution-treated specimen showed brittle-fracture at 196℃, but the low-temperature toughness was improved greatly by resolution treatment at temperature range of 650℃ to 750℃ above A point for short time. The grain size of austenite was refined with resolution treatment time due to recrystallization of austenite, but the toughness was decreased by occurring intergranular-fracture. The martensite formed from the unrecrystallized reversed austenite showed fine block structure within a grain and zig-zagged prior austenite grain boundary. Grain boundary strengthening by the latter seems to be more effective to considerable improvement in low-temperature toughness.