Your Allies in Alloys for over 50 Years

© Avon  Metals Ltd 2017. All rights reserved.

Avon Logo made in britain

Avon Metals Ltd

Dimensional accuracy and internal structure can assess the quality of a casting. Both will influence strength and performance and characterise its value in terms of service. Foundry practice has learnt that structure control during solidification plays a vital role in the achievement of high integrity castings.


In castings the two most important metallurgical features are:-


GRAIN REFINEMENT: for the macrostructure

A casting is a compact network of individual grains.  The size, shape and bonding of these grains will determine the mechanical properties and soundness of the casting, so there is a real need to control their formation.


SILICON MODIFICATION: for the microstructure

Aluminium alloys containing up to 14% Silicon will solidify naturally into coarse, brittle plates of Silicon in a medium of Aluminium. The mechanical strength and ductility of such a casting will be poor and its use limited.


Modification of AISi into a fine, fibrous microstructure brings a marked improvement in properties. Fast cooling will achieve the modified AISi structure, but the presence of Strontium produces a similar effect that exists for several hours under normal foundry conditions. Strontium additions are typically introduced in the form of an aluminium based Master Alloy during melt preparation.


> Titanium to 10%


> Strontium to 10%


> Zirconium to 10%


> Vanadium to 10%