Experimental Investigations On The Mechanical And Microstructural Characteristics Of Friction Welded Aa6061 Sic Graphite Hybrid Composites

Abstract

Friction welding (FW) is a most demandable process among the solid state welding family, due to its quick fabrication time and simple procedure. Moreover, the FW process eliminates the issues associated with the fusion welding process. The demand for the aluminum (AA6061) matrix hybrid composites (AMHCs) in the aerospace and automation industries keep on increasing with references to its special features. On the other hand, the joining of material by welding is inevitable since it is an integral part of the fabrication process in the same automation field. Hence the present research attempt was made to study the effect of friction welding conditions on mechanical and metallurgical properties of the AMHCs (AA6061/SiC/Graphite) joints. The stir casting method adjoining hot extrusion process was used to manufacture hybrid composites in rod form with the following fraction of AA6061 85 %, silicon carbide 10 % and the graphite 5%. Hence the AMCHs rod of 12 mm diameter, 60 mm length was used as base metal to fabricate the FW joints. Further, the RSM adopted to optimize the friction welding process parameters to maximize the tensile properties of the AMHCs (AA6061/SiC/Graphite) joints. The maximum tensile strength of 167MPa was obtained at the rotational speed of 1600 rpm, newline newline newline newlineupset load of 3.5 kN and upset time of 3s. Following this, the effect of rotational speed, upset load and upset time on the mechanical and metallurgical properties of the AMHCs joints have been investigated individually. After this, the post weld heat treatment such as AA, ST and STA were applied to as welded joints to enhance the AMHCs joint properties. Moreover OM, SEM. TEM, and EDAX were used to characterize the AA6061/SiC/Graphite joints across the various regions. Finally the results of PWHT reveals that the STA treated joints produced the highest tensile strength of 189 MPa when compared with other heat treated specimens and the improvement in tensile strength is about 13 % with reference to AW joint. newlineKeywords: Fricti