Effect of Minor Amounts of Scandium on Recrystallization Behavior of ۷۰۰۰ series Aluminium

In the present study, the effect of adding minor amounts of scandium and zirconium elements to the ۷۰۷۵ alloyon the re-crystallization behaviour of one aluminium alloy (۷۰۰۰ series) was investigated. For this purpose, two kinds of Al-Zn-Mg-Cu-Sc-Zr alloys with the same amount of Zr and different amount of Sc were prepared. Homogenization durations and temperatures of alloys after alloying were obtained by DSC analysis and optical microstructure observations. The results showed that the optimum homogenization temperatures for Al-Zn-Mg-Cu-۰.۰۵Sc-۰.۱Zr and Al-Zn-Mg-Cu-۰.۱Sc-۰.۱Zr alloys were ۵۰۰۰C and ۴۹۰۰C respectively, and the optimum duration for both alloys was ۱۲hours. After homogenization of alloys, the re-crystallization behaviour of the alloys was investigated by Brinell hardness test. Obtained results showed that although the starting re-crystallization temperature for both alloys was similar in ۲ hours, but it was ۱۳۰°C for alloys with ۳۰% forming, and ۱۲۰°C for alloys with ۵۰%forming and recrystallization temperature for Al-Zn-Mg-Cu-۰.۱Sc-۰.۱Zr alloy was ۳۵۰in ۲ hours. Despite what was expected, the hardness of Al-Zn-Mg-Cu-۰.۰۵Sc-۰.۱

کلیدواژه ها:

Recrystalyzation ، Al-Zn-Mg-Cu-Sc-Zr ، ۷۰۰۰ series aluminium