Developed by Drouzy et al.  the concept of the quality index, Q, is capable of expressing the materials mechanical quality in terms of a single numerical parameter. The performance of the alloy can be quantitatively expressed in terms of Q, to show performance improvements or otherwise.
The strength of Aluminium-Copper casting alloys is dependant on the copper (Cu) and magnesium (Mg) for given heat treatment while the tensile ductility may be affected by the iron (Fe) and porosity content, etc. When different process routes are followed or the chemical composition is changed, the balance between the different factors affecting the strength and ductility of the alloys usually changes. Hence the quality index can be a very useful tool to assess any improvement or otherwise in the mechanical properties of the alloy.
Quality index charts exist for A356 and A357 alloys, but they need to be developed for alloy A206, which is one of the goals of this work. The other will involve exploring a range of heat treatments in an attempt of optimising the strength and ductility of the material.