MICROSTRUCTURE AND MECHANICAL-PROPERTIES OF 5056-AL-ALLOY PROCESSED BY EQUAL CHANNEL ANGULAR EXTRUSION

Equal channel angular extrusion (ECAE) was carried out at 373 and 523 K for a 5056 Al alloy. The alloy processed by ECAE at 373 K consisted of a very fine-grained structure with a grain size of about 0.5 mu m a nd a dislocation cell structure. On the other hand, for the alloy proc essed by ECAE at 523 K, the structure was uniform and a small grain si ze of about 2 mu m was attained. The alloy processed by ECAE at 373 K showed higher room temperature strength. On the other hand the alloy p rocessed by ECAE at 523 K exhibited no improved tensile properties, co mpared to the as-received alloy. Both alloys processed by ECAE exhibit ed a lower flow stress and a larger elongation at 573 K than the as-re ceived alloy. This is probably attributed to grain boundary sliding. ( C) 1998 Acta Metallurgica Inc.