Experimental Determination of GrAln Density Function Dependence on Particles Size and under Cooling in AZ91/SiC Composites Nucleation Model
Magnesium alloys and their composites have been attracting increasing attention due to lightweight which are being utilized in the automobile and aerospace industries. The Alm of this paper was to determine fitting parameters in grAln density of the magnesium primary phase function in AZ911SiC composite heterogeneous nucleation model. This function as an element of heterogeneous nucleation model can be connected with grAln growth model to obtAln mathematical description of nucleation and crystallisation phenomena. Those equations, which takes into account also chemical elements diffusion and grAln interface kinetics, can be used to predict casting quality and its microstructure. Nucleation models have parameters, which exact values are usually not known and sometimes even their physical meaning is under discussion. Those parameters can be obtAlned after mathematical analyze of the experimental data. Specimens of fourteen different composites were prepared. The matrix of the composite was AZ91 and the reinforcement was SiC particles. The specimens differs in SiC particles size (101Jm, 401Jm, 761Jm) and content (0 wt.％ , 0. 1 wt.％ , 0.5 wt.％,2 wt.％, 3.5 wt.％). They were taken from the region near to the thermocouple, to analyze the under - cooling for different composites and its influence on the grAln size. The specimens were polished and etched. The mean grAln size for each specimen was measured. Specific under - cooling for each composite was found from characteristic points on cooling rate curve. Described above microstructural analyze and thermo-analyze gave set of values that connect SiC particles content, their size and alloy under-cooling with grAln size. This values were used to approximate nucleation model adjustment parameters. ObtAlned model can be very useful in modelling composites microstructure.
heterogeneous nucleation AZ911SiC composite grAln density function SiC particles size mathematical modelling
P. Zak J. Lelito J. S. Suchy W. Krajewski K. Haberl P. Shumacher
AGH University of Science and Technology, Krakow, Faculty of Foundry Engineering, Department of Foun University of Leoben, Department of Metallurgy,Chair of Casting Research, Franz - Josef - Strasse 18
国际会议
69th World Foundry Congress(第69届世界铸造会议 WFC 2010)
杭州
英文
462-466
2010-10-16（万方平台首次上网日期，不代表论文的发表时间）