Effect of the matrix structure on vermicular graphite cast iron properties

Abstract

Abstract Vermicular graphite cast iron (VGCI) prepared via the sandwich process was treated by annealing, and the microstructure and the mechanical and damping properties before and after the annealing treatment were studied. The graphite size, distribution and morphology did not change significantly after annealing. However, the matrix transformed from ferrite + pearlite to ferrite after annealing, the dislocation density decreased significantly, and the interfacial stacking faults between the matrix and graphite disappeared. The annealing treatment reduced the tensile strength by >12%, but increased the strain-to-fracture value to two times that of the as-cast sample. The damping properties varied with temperature with obvious S-K peaks and Ge peaks. The maximum internal friction changed from 0.023 (as-cast) to 0.011 (post-anneal).