THE EFFECT OF ALLOYING ON THE MECHANICAL PERFORMANCE AND SUBSTRUCTUREOF ALUMINUM AT LARGE STRAINS

The Al-5Mg alloy, and the differential purity aluminium Al99.992 and A l99.5 samples were deformed in the range of true strains from 0.2 to a bout 80. The course of hardening of materials was found to be differen t. The proof stress of Al99.992 and Al99.5 saturates above the true st rain of about four and eight, respectively. In Al-5Mg alloys, proof st ress increases in the whole investigated range of deformations, showin g however stepwise course with two 'plateaus' of the proof stress stab ilization. The observations of microstructure show presence of microba nds in all materials. In Al99.992 and Al99.5 microbands assume the for m of thin elongated, free of dislocations subgrains. In Al-5Mg alloy m icrobands look like thin layers of high, local dense dislocations. (C) 1997 Elsevier Science S.A.