文档介绍：Microstructural Evolution in Graphite Iron During High Temperature Annealing
S. Ghodrat1,2, M. Janssen2, . Kestens2,3, and J. Sietsma2
1) Materials innovation institute (M2i), Mekelweg 2, 2628 CD, Delft, herlands
2) Department of Materials Science and Engineering, Delft University of Technology
Mekelweg 2, 2628 CD, Delft, herlands
3) Department of Materials Science and Engineering, Ghent University, Technologiepark
903, 9052 Gent, Belgium
Email: s.******@
Abstract
Compacted Graphite Iron (CGI) has been widely employed for manufacturing ponents over the last decades. ponents, such as cylinder blocks and heads, are exposed for long times at elevated temperatures or subjected to prolonged periods of cyclic heating and cooling. These conditions may give rise to the position of the pearlite matrix panied by the formation of lower-density graphite and the formation of oxides, which will lead to an increase or growth of material volume. The extent of pearlite position and oxidation depends on number of operating conditions such as maximum temperature and exposure time but also on material parameters such as the position and the graphite morphology, which is of particular interest for internal oxidation. The microstructural instability deteriorates the physical and mechanical properties of CGI and accordingly the thermal fatigue properties.
The data presented here are obtained from growth measurements at 420°C for different exposure times. In order to quantify the oxide layers surrounding the graphite particles both Energy and Wavelength dispersive X-ray spectroscopy was carried out in the Scanning Electron Microscope. Moreover, to better understand the effect of temperature on the microstructural evolution, dilatometer tests were carried out at 500, 550, 600, 650 and 700 ˚C for 16 h in vacuum condition. This helped us to discern the effect of oxygen in decarburization and the formation of the oxide layers as well. I would not include this paragraph. I