Spheroidal graphite cast iron GGG 40 was thermo-mechanically tested using thermo-mechanical simulator Gleeble-3500. Three deformation steps were successively applied on test-specimen at temperatures namely;900°...Spheroidal graphite cast iron GGG 40 was thermo-mechanically tested using thermo-mechanical simulator Gleeble-3500. Three deformation steps were successively applied on test-specimen at temperatures namely;900°C, 850°C and 750°C within the austenitic zone, at the same strain rate of 0.1 s-1. No cracks were observed, up to 50% deformation, after successive deformation steps. Stress-strain relationship obtained is correlated with previous work on SGCI with a different carbon equivalent. It was found that by decreasing the deformation temperature;for the same CE, young’s modulus, yield strength and strain hardening exponent increase. Microstructure of the deformed zone, for a specimen quenched after the final deformation step, reveals fine elongated ferrite and pearlite, as well as elongated graphite. While microstructure of the non-deformed zone subjected to the same treatment, includes coarser ferrite and pearlite with graphite spheres embedded in the matrix.展开更多
In the present work, a new method to predict the stress-strain curves for three-phase materials has been developed. It was applied using the example of an Mg-stabilized zirconia reinforced TRIP-matrix-composite. The c...In the present work, a new method to predict the stress-strain curves for three-phase materials has been developed. It was applied using the example of an Mg-stabilized zirconia reinforced TRIP-matrix-composite. The content of the ceramic phase was varied between 5% and 20%, whereas the particle size of the ceramic was selected to be 30 to 50 μm. The method is a further development of mixture rule for multiphase materials with more than two microstructure components. The prediction results were compared with the original method of mixture rule and with the IsoE-method. It is shown that the new method significantly improves the convergence compared to the standard method for mixture rule, even though it does not reach the accuracy of IsoE-method. Furthermore, there is an improvement of predicted convergence for large values of the total stress. Finally, a working map was designed for a quick graphical definition of the objective functions.展开更多
文摘Spheroidal graphite cast iron GGG 40 was thermo-mechanically tested using thermo-mechanical simulator Gleeble-3500. Three deformation steps were successively applied on test-specimen at temperatures namely;900°C, 850°C and 750°C within the austenitic zone, at the same strain rate of 0.1 s-1. No cracks were observed, up to 50% deformation, after successive deformation steps. Stress-strain relationship obtained is correlated with previous work on SGCI with a different carbon equivalent. It was found that by decreasing the deformation temperature;for the same CE, young’s modulus, yield strength and strain hardening exponent increase. Microstructure of the deformed zone, for a specimen quenched after the final deformation step, reveals fine elongated ferrite and pearlite, as well as elongated graphite. While microstructure of the non-deformed zone subjected to the same treatment, includes coarser ferrite and pearlite with graphite spheres embedded in the matrix.
文摘In the present work, a new method to predict the stress-strain curves for three-phase materials has been developed. It was applied using the example of an Mg-stabilized zirconia reinforced TRIP-matrix-composite. The content of the ceramic phase was varied between 5% and 20%, whereas the particle size of the ceramic was selected to be 30 to 50 μm. The method is a further development of mixture rule for multiphase materials with more than two microstructure components. The prediction results were compared with the original method of mixture rule and with the IsoE-method. It is shown that the new method significantly improves the convergence compared to the standard method for mixture rule, even though it does not reach the accuracy of IsoE-method. Furthermore, there is an improvement of predicted convergence for large values of the total stress. Finally, a working map was designed for a quick graphical definition of the objective functions.
