Abstract
Precipitation behavior of directly cold-rolled and prior to hot roll Al-5Mg alloy with ternary zirconium has been examined. Hot-rolled and cold-rolled alloy samples are aged simultaneously isochronally and isothermally for different temperatures and times. Hardness, resistivity, impedance value, and DSC study have been considered to comprehend the precipitation behavior of the differently aged alloys. No age-hardening response is observed for all the alloys, but the directly cold-rolled Zr-added alloy resists the soften behavior than that of prior to hot roll alloy. Precipitation kinetics of Al₃Zr in Al-5Mg-0.3Zr alloys is controlled by the diffusion of zirconium in aluminum. Microstructures display that the Al-5Mg alloy becomes almost fully recrystallized after aging at 300 °C for 300 min. But Zr-added alloys do not show this scenario owing to the presence of metastable fine L1₂ Al₃Zr precipitates, which are thermally stable at high aging temperatures.

Key words
Al-Mg alloys, rolling, resistivity, precipitation, DSC, microstructure

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