Impression creep deformation behaviour of FSWed AA6061 at various weld zone

Abstract

ABSTRACT Impressioncreep (IC) tests were performed at three welded regions viz: nugget zone (NZ), thermo-mechanical affected zone (TMAZ) and heat affected zone (HAZ) at 326°C, 359°C and 378°C of furnace temperature and equivalent stresses of 24MPa, 28MPa and 32MPa respectively. The high temperature deformation properties were estimated by employing power law creep equation and the results were compared with the base material (BM). The rate controlling mechanism of IC process at each selected area and its correlation with the microstructural evolution throughout FSW and IC procedures were realised. The steady-state creep rate of NZ was estimated to be the highest and of BM was the lowest. The other creep parameters such as the stress exponents and the apparent activation energy for the IC process were calculated at each localised zones for the welded material and were compared with the BM. The creep deformation was found to be homogeneous at all the selected testing areas and was of dislocation type. Creep rate was found to be affected by the grain size and testing temperature. Detail microstructural analysis of the samples before and after the IC test was performed by optical microscope.