Effect of Annealing Treatment on Microstructure, Mechanical and Damping Properties of Ductile Iron

Abstract:

Ductile iron was prepared through Sandwich Process and annealing treatment was carried out. The effects of annealing treatment on the microstructure, mechanical and damping properties of ductile iron were studied by means of metallographic microscope, scanning electron microscope, transmission electron microscope, universal test machine and dynamic thermal mechanical analyzer. The results show that annealing treatment has little effect on the morphology and distribution of graphite cast iron, but it will lead to the decrease of pearlite content in the matrix, the increase of ferrite content and the disappearance of cementite. Annealing transforms the fracture form of ductile iron from cleavage fracture to quasi-cleavage fracture, which greatly increases the ductile fracture area of the matrix compared with the as-cast, and tends to develop ductile fracture. The annealing treatment results in a decrease in the tensile strength of the ductile iron, but it can increase the plasticity and increase the elongation after fracture to 7.5 times that of the as-cast state. The damping value of as-cast ductile iron increases first and then decreases with the increase of temperature, and peaks at 190 °C when Q^-1 is 0.025. The damping value of annealing ductile iron decreases with increasing temperature. The damping value increases with increasing strain amplitude before and after annealing. Annealing treatment will reduce the sensitivity of the damping property of ductile iron to strain amplitude.

• Periodical: Materials Science Forum (Volume 944)
• Pages: 222-228
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.944.222
• Online since: January 2019
• Authors: Yu Zhang*, Er Jun Guo, Li Ping Wang, Yi Cheng Feng, Si Cong Zhao, Mei Hui Song
• Keywords: Annealing Treatment, Damping Property, Ductile Iron, Mechanical Properties, Microstructure

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