Microstructure and Mechanical Properties of Ductile Cast Iron in Lost Foam Casting with Vibration

The microstructures and mechanical properties of the ductile cast iron (Dl) specimens obtained by lost foam casting (LFC) with and without vibration were investigated. The results indicate that the number of the graphite nodule increases from 173 mm−2 of the specimens produced by LFC without vibration to 334 mm−2 of the specimens produced by LFC with vibration, and the thickness of the ferrite shell increases. Meanwhile, the amount of the carbides decreases in the specimens produced by LFC with vibration and the granule structure then forms. These are mainly attributed to the “crystal shower” caused by the vibration. In addition, the tensile strength and elongation of DI specimens produced by LFC with vibration are improved due to the dispersion-strengthening of refined carbide and pearlite colony, uniform distribution of the graphite nodule, and increase of the amount of dimples and tearing edges.