Influence of microstructure on the formability of Al-Mg6.8 alloy

Formability of Al-Mg6.8 alloy has been evaluated experimentally in uniaxial tension and biaxial stretching. Three different structures developed after cold rolling and annealing in the range of temperature from 265 to 320 ?C: (I) recovered dual (a + ?) phase, (II) recrystallized (a + ?) dual phase, and (III) recrystallized a-Al single phase structure, were tested. Samples with recovered structure have shown a lower formability level than the samples with fully recrystallized structure. Formability level assessed through FLD and LDH value, has been a result of complex interaction between work hardening ability and strain rate sensitivity. U ovom radu koriscena je aluminijum-magnezijum legura sa 6,8% magnezijuma (Al-Mg6,8), koja pripada grupi Al-Mg legura visoke cvrstoce. Ispitivan je uticaj mikrostrukture, koja se postize primenom razlicitih uslova termomehanicke obrade (TMO), na deformaciono ponasanje pri jednoosnom zatezanju, i na sposobnost oblikovanja u uslovima slozenog naponsko-deformisanog stanja. Najbolju sposobnost oblikovanja, koja je ocenjena na osnovu parametara ojacavanja u toku jednoosnog zatezanja, i na osnovu granicnih krivih oblikovanja (GKO), konstruisanih po kriterijumu lokalnog stanjivanja i granicne visine kupole (GVK), pokazuje ispitivana legura sa rekristalisanom jednofaznom a-Al i/ili dvofaznom (a + ?) strukturom.