By comparing the welds of an alloy of aluminum 7075 realized by thetechnique of soldering TIG with those of the same alloy after heat treatments,we notice an improvement of the mechanical properties of hardness; thevalues in HAZ have relatively increased with regard to the other zones of thewelds. The microstructural state was modified; this is can be attributed to thecombination of heat cycles and treatments. Heat treatments have preserved relatively the microstructural and mechanicalproperties in the 3 essential zones of the weld. The facieses of break in the various zones show that the break was ductile setapart in the melted zone where the break was mixed (ductile-fragile) The characterization of the microstructure requires the use of techniques ofinvestigation (optical microscope and electron microscope with sweeping) for local approaches, and the indexation of the phases by diffraction (x rays) forglobal approaches, it also requires the use of impact strength test to estimatethe quality of the weld.
