FRACTURE CHARACTERISTIC OF DISPERSION STRENGTHENED AL-AL4C3 MATERIAL DURING CREEP

Dispersion strengthened materials offer superior behaviour at high temperatures and are characterized by particularly good creep resistance. Rupture behaviour of Al - A14C3-materials with 5 vol.% dispersoid was investigated accurately with respect to rupture creep behaviour. Different creep processes are going on simultaneously, the most dominant one being the diffuse climbing of the dislocations. This phenomenon results in small elongations at rupture at low creep tensional stresses cohereas dynamic polygonisation leads to high elongations at high creep stresses. Differences between the yield strength in tensile and compressive measurements are indicative for premature creep failure caused by debonding processes at the grain boundaries.