The impact of submerged friction stir processing on the friction stir welded dissimilar joints

Abstract

The submerged friction stir processing (SFSP) technique was employed on the prior friction stir welded (FSW) AA6082/AA8011 dissimilar aluminum alloy joints. The tap water with room temperature was kept at 40 mm depth throughout the processing. The AA6082 was kept at the advancing side during FSW and SFSP process and this was done to enhance the strength of the joint. The SFSP joints were studied comparatively with the FSW joints. The sampling position was also studied for both the FSW joint and SFSP joint. The employment of the submerged friction stir processing resulted in the microstructural grain size refinement. The tensile strength of the SFSP joint was found to be higher than that of AA8011 base metal but lower than that of AA6082 base metal. The tensile strength of the FSW joint was found to be lower than that of both base metals. There was a clear correlation between the tensile properties and the grain size refinement. The SFSP joint exhibited good microhardness properties compared to the FSW joint.

The Influence of Multiple Pass Submerged Friction Stir Processing on the Microstructure and Mechanical Properties of the FSWed AA6082-AA8011 Joints

“…The 1-pass friction stir-processed FSWed joints had a mean grain size range of 13.17 to 16.51 µm, minimum grain size range of 3.29 to 3.63 µm and a standard deviation range of 4.32 to 6.42 µm. Similar results were reported in the literature [17]. The 2-pass friction stir-processed FSWed joints had a mean grain size range of 7.03 to 7.51 µm, standard deviation range of 2.12 to 3.56 µm and minimum grain size of 3.04 to 4.12 µm.…”

Effect of Heat Treatment on the Mechanical Properties of a 3 mm Commercially Pure Titanium Plate (CP-Ti Grade 2)

“…e microstructure of the parent materials is shown in Figure 4(a), while Figures 4(b)-4(d) show the microstructure of the samples heat treated for 30 minutes, 60 minutes, and 90 minutes, respectively. e average grain size (presented in Table 3) of each sample was measured by the use of linear intercept technique through ImageJ software [35]. e generic CP-Ti microstructure composed of alphaphase was observed during microstructural analysis.…”

“…e decrease in UTS for the heat treated samples could be as the results of the annealing temperature which encouraged the transformation of alpha phase [13,32,[36][37][38]. e decrease in UTS was however accompanied by the increase in percentage elongation for all the heat treated samples and this is normal in metals [13,[34][35][36][37][38]. e increase in percentage elongation suggests that the increase in ductility of the material [32][33][34].…”

“…e Motic AE2000 microscopy was employed in conducting the microstructural analysis [33][34][35]. e tensile samples were prepared according to the ASTME646-98, and the performance of tensile tests was also based on the same standard.…”

“…ere was a significant drop in ultimate tensile strength (UTS) in all the heat treated samples compared to the parent material. e decrease in UTS is caused by the grain growth which is defined by the Hall-Petch relationship [26,28,35]. e decrease in UTS for the heat treated samples could be as the results of the annealing temperature which encouraged the transformation of alpha phase [13,32,[36][37][38].…”