Effect of multi-pass friction stir processing and Mg addition on microstructure and tensile properties of Al-1050 alloy
19 February 2020
Revised: 20 April 2020
Accepted: 21 April 2020
Available online: 24 April 2020
Abstract: The effect of multiple passes of friction stir processing (FSP) and the addition of Mg powder on different parts of the microstrcuture processed including the stir zone (SZ), the heat-affected zone (HAZ), and the thermo-mechanically affected zone (TMAZ) were investigated. The results of the microstructural observations revealed that although the grain size of the SZ decreased in both the non-composite and composite samples, the grain size increased in the TMAZ and the HAZ of the non-composit sample with increasing the numer of FSP passes. Besides, the addition of Mg powder resulted in much more significant grain refinement. Moreover, increasing the number of the FSP passes resulted in a more uniform distribution of Al-Mg intermetallic compounds in the in-situ composite sample. The results of the tensile testing showed that the four- passes FSPed non-composite sample exhibited a higher elongation percentage with a ductile fracture compared with those of the base metal and the four-pass composite sample while lattermost sample exhibited a brittle fracture and a higher tensile strength value than the base metal and the four-pass FSPed non-composite sample. The fabrication of composite samples resulted in noticeable enhancement of hardness compared with the base metal and the non-composite FSPed samples.