Damping capacity of graphite-dispersed composite steel

Abstract

Composite steels consisting of an iron-graphite sintered core and steel were prepared by powder metallurgy and their damping capacities were examined. The ferritic grain size in the sintered core decreases with increasing carbon (graphite) content, resulting in a decrease in internal friction due to magnetic domain wall movement. Conversely, internal friction due to the deformation of graphite increases with carbon content. The internal friction of graphite-dispersed composite steel reaches a maximum at a carbon content of approximately 5 mass%. When carbon content exceeds 12 mass%, delamination between the steel part and the sintered core occurs easily and a good composite steel cannot be obtained. Experimental results suggest that a high damping capacity can be provided by appropriate control of the microstructure of the steel part and the ferritic grain size and carbon content of the sintered core.