Processing understanding, mechanical durability and hygrothermal stability of PC/AA6061 hybrid joints produced via injection overmolding

In the present study, single-lap joints of polycarbonate (PC) and laser-textured aluminum alloy AA6061 were manufactured by injection overmolding (IOM) and characterized in terms of the microstructure, quasi-static and long-term mechanical performance and hygrothermal stability. The injection overmolding parameters were optimized through design of experiments and analysis of variance, which showed that the parameters of barrel temperature, injection speed and holding pressure positively affected the ultimate lap-shear force (ULSF). PC/AA6061 injection overmolded hybrid joints exhibited outstanding joining strength of 7.2 ± 0.5 MPa. Under fatigue cyclic loading, hybrid joints produced with optimized IOM processing conditions showed a fatigue life of 35 % ULSF at 106 cycles, demonstrating excellent mechanical durability. Moreover, PC/AA6061 injection overmolded hybrid joints showed good hygrothermal stability, with no significant variations in joining strength after aging in water at 80 °C for 30 days.