X-RAY-POWDER DIFFRACTION STUDY OF FEW AL-4.5 AT-PERCENT ZN-X AT-PERCENT MG ALLOYS

Seven Al-4.5 at% Zn-x at% Mg alloys, with x ranging between 0 and 3.0, are studied by X-ray powder diffraction. The following measurements a re performed: (i) the dependence of the lattice constant of the a-phas e of the as-quenched and the slowly cooled alloys on x at RT, (ii) the thermal expansion of the equilibrium eta(MgZn2)-phase and its dissolu tion in the alpha-phase at elevated temperatures. It turns out that in particular the analysis of the lattice constant of the matrix, alpha, results in valuable information about the amount of solved atoms of t he alloyed elements and the matrix stresses.