Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

Final Activity Report Summary - CASTMODEL (Development of environmentally friendly cast alloys and composites)

The CASTMODEL project was aimed at the transfer of knowledge in the area of development of the environmentally friendly cast alloys and composites. The developed alloys should be concurrent with the traditional Fe-based ones, which are more energy consumable. Replacing some amount of Fe-based alloys with the less energy consumable ones, e.g. Al-Zn or Mg-Al, is also very important for energy saving and human environment protection. However, the replacing can be possible after improving properties of the selected Al-Zn and Mg-Al based alloys. According to the formulated main aims of the project the examinations were focused on grain-refinement of the high-aluminium zinc alloys (HAl-Zn alloys) and high-zinc aluminium alloys (HZn-Al alloys). The refinement aimed at improving ductility was performed by introducing grain refining master alloys to the melt. The alloys selected to the investigations were: ZnAl25 alloy (a representative of the HAl-Zn alloys) and alloy AlZn20 (a representative of the HZn-Al alloys). The structure refinement was performed by using traditional master alloys, i.e. TiBAl (AlTi5B1) and TiCAl (AlTi3C0.15).

During the project newly elaborated master alloys, i.e. binary Zn-Ti (e.g. ZnTi4) and ternary ZnAl-Ti (e.g. ZnAl-Ti3) were used. The Al-Zn alloys are very prone to surplus overheating which can cause melt oxidation and decrease of the properties, as well as increase of the metallurgical metal lost. The elaborated master alloys ZnTi and ZnAl-Ti have good solubility in a melt of comparatively low temperature of 550 oC as well as mass density close to the melted alloys densities. These features allow the avoidance detrimental overheating of the inoculated Zn-Al alloys, which is required when the traditional Al-Ti MAs are used. During the project it was stated that the binary Zn-Ti master alloys are more effective for the HAl-Zn alloys while the ternary ZnAl-Ti ones should be used when melting the HZn-Al alloys. Both high-aluminium zinc alloys and high-zinc aluminium alloys are known to be the high damping alloys. It is well known that surplus grain refinement can decrease damping properties. During the project the range of grain refinement was investigated to obtain ductility increase with high damping and strength properties preserved, e.g. to obtain complex of good properties.

The second research direction was transfer of knowledge concerning casting technologies of the MgAl-base cast composites. It was connected with modelling of the primary structure formation after pouring the alloy into mould. Within this area SiCp particles were used as the reinforcement. Together with the composite structural examinations the numerical modelling was developed. A numerical model of the MgAl-SiC crystallisation process was elaborated, which allows us to forecast the structural features (e.g. structure fineness) - directly connected with properties of the solidified casting. The elaborated numerical model is the key instrument in rational control of the crystallisation process needed to obtain required final structure and properties of the castings.

The third main aim of the project was development of the scientific collaboration and transfer of knowledge between Polish and main European scientific centres in the Metallurgy and Materials Science field. The excellent collaboration between the Polish teams led by the project coordinator prof. Witold K. Krajewski (Al-Zn and Mg-Al based cast alloys and composites) and prof. J.S. Suchy (modelling) and the teams led by prof. A.L. Greer (University of Cambridge) and prof. P. Schumacher (University of Leoben) allowed organising several scientific meetings and seminars in Cambridge and Krakow as well as performing all the planned trainings in the area of melting, casting as well as structural and properties examinations.

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