The Impact Of The Chemical Composition Of The Organization And Performance Of Aermet100 Steel

This paper shows the results of research on the microstructure and mechanical properties due to adding RE and the different content of composition of AerMetlOO, known as the secondary hardening ultra-high strength steel. In this study, the mechanical properties were test. In additional, the microstructure of the alloy was analyzed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM).Through research found that the influence of carbon content is remarkable to the mechanical properties of experimental steel. With the increase of carbon content the strength and hardness of experimental steel gradually improved and the impact toughness and fracture toughness gradually decreased. Some quasi-cleavage morphologies appear in impact fracture with the increase of the carbon content in the experimental steel, while the aging peak increase gradually, but its position unchangeable.With the increase of chromium content the strength and toughness of steel did not change significantly and the age-hardening peak shifts to lower temperature. With the aging temperature increased the high-chromium steel strength decline faster. The increase of chromium content cause faster over-aging. The chromium addition makes cementite unstable, which promotes the M₂C carbides formed and increases the rate of over-aging in the materials.With the increase of molybdenum content the strength and hardness of steel gradually improved, but the toughness gradually decreased, quasi-cleavage morphologies increase. Increasing the molybdenum content of the alloy would be increase the driving force for M₂C precipitation, and increase the peak hardness, while reverted austenite reduced, therefore reducing the plasticity and toughness of the steel.The influence of cobalt is relatively remarkable to the mechanical properties of experimental steel. With the increase of cobalt content the strength and hardness of steel gradually improved, while the toughness decreased, and quasi-cleavage morphologies increase in impact fracture. The cobalt addition promotes austenite change to martensite and the formation of the M₂C carbides. Thus the strength of steel increase, toughness reduces with the increase of cobalt content.With the increase of nickel content the toughness of steel gradually raised, dimples increase, quasi-cleavage reduces. The aging curve of strength shifts to lower temperature with the nickel content increase. That is, the nickel increases result in earlier over-aging in experimental steel. The nickel addition promotes the dissolution of M₃C cementite and thus makes fine M₂C carbides formed at lower temperatures.The addition of RE causes the inclusion modification, formed the round or oval-shaped RE inclusion. And it has changed the distribution of inclusions, makes mean spacing of inclusions increases. Therefore the toughness of steel will be improved.