Experimental Determination of GrAln Density Function Depends on Mass Fraction of SiC and Undercooling in AZ91/SiC Composite Heterogeneous Nuclation Model
Magnesium alloys and their composites have been attracting attention as an important lightweight material and are being utilized in the automobile and aerospace industries. In terms of the reinforcement in magnesium - based composites, the SiC particles are extensively used because magnesium cannot form any stable carbide. The grAln density in the solid state Nv after solidification of AZ911SiC composite is a function of maximum undercooling of a liquid alloy 1::, T. This type of function depends on the characteristics of heterogeneous nucleation sites and number of SiC present in the alloy. The Alm of this paper was selection of parameters for the model describing the relationship between the grAln density of primary phase and undercooling. This model in connection with model of crystallisation, which is based on 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. The composite with 0,1,2,3 and 4 wt.％ of SiC particles were prepared. The AZ91 alloy was a matrix of the composite reinforcement SiC particles. This composite was casted to prepare four different thickness plates. They were taken from the region near to the thermocouple, to analyze the undercooling for different composites and thickness plates and its influence on the grAln size. The microstructure and thermo analyze gave set of values that connect mass fraction of SiC particles,and undercooling with grAln size. These values were used to approximate nucleation model adjustment parameters. ObtAlned model can be very useful in modelling composites microstructure.
heterogeneous nucleation mass fraction of SiC particles AZ911SiC compositerqrAln density mathematical modelling
J. Lelito P. Zak J. S. Suchy W. Krajewski A. L. Greer P. Darlak
Department of Foundry Engineering Processes, AGH University of Science and Technology, Mickiewicza 3 Department of Materials Science & Metallurgy,University of Cambridge, Pembroke Street, Cambridge CB2 Foundry Institute,Zakopianka 73,30 -418 ,Krakow.Poland
国际会议
69th World Foundry Congress(第69届世界铸造会议 WFC 2010)
杭州
英文
456-461
2010-10-16（万方平台首次上网日期，不代表论文的发表时间）