This investigation was conducted to define .the mechanism responsible for the strengthening increase imparted by deformation of metastable austenite. The relationships of mechanical properties to extent and temperature of deformation were developed for Type H-ll hot work die steel. The influence of nonmartensitic decomposition products on properties were determined. The microstructures were studied by thin-film electron transmission methods for observations of martensite morphology and substructures and precipitates. Measurements of subcell sizes and distribution of precipitates were made for comparison with observed mechanical properties through application of dislocation theory. The observed dislocation density and carbide dispersion indicate that the strengthening mechanism active in both ausformed and conventionally heat treated martensitic steels is some combined effect of dislocation-precipitate and dislocation-dislocation interaction.nThis technical documentary report has been reviewed and is approved.
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