Microstructure and thermomechanical properties of CDFW for Al6061/GNPs

The paper provides a novel technique for merging graphene nanoplatelets (GNPs) within an aluminum matrix (AA 6061) by continuous drive friction welding (CDFW). The welding processes were done at 1400 rpm and 2000 rpm rotational speeds with two frictional loads, 2000 N and 2500 N, for 5 sec and 7 sec welding times. The welded joints were subjected to tensile and hardness tests. The heating-cooling cycles through the welding process were monitored. The microstructure was investigated using optical and scanning electron microscopes (SEM). The effect of welding conditions on the ultimate tensile strength (UTS) results of AA 6061 and AA 6061/GNPs was studied in detail. There is no considerable detectable variation in the mean hardness values due to the GNPs addition. The best welding conditions for achieving the highest mechanical properties were defined. The presence of GNPs in the welded joints results in lower heating at the welded joint at the same welding conditions. Finer grain structure and homogeneous distribution for the GNPs within the welding zone were observed.