ISSN:
1573-4803
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract This paper is concerned with theoretical and experimental studies of the dendritic structure and its dissolution in aluminium-zinc alloys. The maximal dendritic microsegregation in the composition range of theα solid solution, as defined by the amount of non-equilibriumα+η eutectic, and the variation in zinc concentration across a model of dendritic grain have been calculated. The measurements of the above mentioned quantities were then performed using quantitative microscopy and X-ray microanalysis. The results obtained for the as-cast Al-Zn alloys confirmed the theoretically predicted data. In order to eliminate such micro-segregation an annealing treatment was applied. Specimens of Al 60wt% Zn alloy (0.383 mole fraction of zinc) showed a significant resistance to the homogenization treatment. This phenomenon can be explained theoretically on the basis of the calculated homogenization relaxation time, and the thermodynamical factor dμ Zn/dN Zn, for several annealed alloys. Both of these quantities achieve their maximum in the composition range 0.30 to 0.40 mole fraction of zinc.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02402755
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