Production of AA1050/silica fume composite by bobbin tool-friction stir processing: Microstructure, composition and mechanical properties

In the present study, bobbin tool friction stir processing (BT-FSP) with a cylindrical pin was utilized to produce bulk processed AA1050 and AA1050/6.5 vol% silica fume (SF) composite at a rotation speed of 600 rpm using two travel speeds of 100 and 200 mm/min. The BT-FSP temperature was measured for both processed materials. Phase composition, relative density, macrostructure, hardness, ultimate tensile strength, and compressive strength were examined for the AA1050 base material, processed AA1050 and AA1050/SF composite. The results showed that the temperature of BT-FSP was increased with SF addition. The addition of fine SF resulted in a small crystallite size compared to the AA1050 BM and the processed AA1050. Moreover, the SF addition to the AA1050 matrix improved mechanical properties in terms of hardness, ultimate tensile strength, and compressive strength compared to AA1050 BM and processed AA1050. The bulk AA1050/6.5 vol% nano SF composite produced at 600 rpm and 200 mm/min showed remarkable enhancements in properties compared to AA1050 parent material; i.e. 50% in hardness, 11% in compressive strength, and 40% in ultimate tensile strength.