High Temperature Tensile Behavior of FeO Scale

High-temperature mechanical properties and deformation behavior of wustite scale were investigated. Tensile tests of oxide scale were performed from 600 to 1200°C under strain rates of 10−3∼10−5 s−1 in a gas atmosphere of H2-H2O-N2. Scale chemistry during the tensile test was maintained. Test specimens of wustite scale were prepared by complete oxidation of 99.999%Fe in a corresponding gas atmosphere before the tensile test. Oxide scale of wustite deformed plastically above 700°C. Fracture elongation increased and tensile strength decreased as the temperature increase; elongation of 150% was obtained at 1200°C. Steady-state deformation, where the stress saturated, was recognized above 1000°C. Sub-boundary structure due to polygonization was observed for the test specimen after tensile test. The test results suggest that high-temperature deformation of wustite scale results from dynamic recovery associated with dislocation climb above 1000°C.