Composite alloys Al-Cd; Al-Cd-Bi and Al-Cd-Bi-Pb are characterized by thermal, X-ray and microscopic studies. The composite alloys are grown at different modes of solidification to understand comprehensively the intrarelationship among Lamellae of the constituent materials comprising their respective solidus structures. X-ray diffraction studies affirm composite alloys to be a terminal solidus solution of physically distinct and mechanically separable phases. Growth habits and thermal stability of composite phases are ascertained using SEM and DSC. The variation of an anisotropic mechanical property over the entire experimental range of growth velocity furnishes an evidence of its dependence as linear, non-linear and linear respectively, in the slow, moderate and fast growth regions of solidification. Evidentially, this generates the strength-growth relationship which follows an identical form of the Weibull probability distribution curve inculcating the obedience of microstructural parameters to the distribution. Consequently, the curve has two cut-off points corresponding to a lower strength limit in the slow and fast growth regions and an upper strength limit in the moderate growth region. The latter is equivalent to the theoretical strength of lamellae, as microstructural parameters obey Gauss distribution in the absence of any surface flaws which are responsible for the reduced strength. Moderate anisotropic growth velocity (~2.90 x 10- 7m3s-1) strengthens the composite microstructures two to three fold of their isotropic growth observed in an icebath (~273 K) and manifold superior to their constituent phases irrespective of growth mode.
