Effect of eutectic particles on the grain size control and the superplasticity of aluminium alloys

Aluminium alloys containing eutectic particles of the Al-Ni, Al-Mg-Si, Al-Ni-Ce and Al-Cu-Ce systems are investigated. The particles which control grain growth and stimulate grain nucleation are studied. The Zener-Smith law about dependence between grain size and particle parameters is confirmed and experimental coefficients are found. Experimental coefficients of the Zener-Smith equation obtained in this study depend on the particle size and differ from theoretical coefficients proposed by Zener and Smith. Some alloys with grain size about 3 mu m demonstrate very good superplasticity indicators, namely: the strain rate sensitivity index m = 0.5-0.6 and the elongation over 400% at constant strain rate 5 x 10(-3) s(-1). Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.