Investigation of the structural properties and corrosion behavior of few-layered graphene reinforced Al-Zn matrix P/M composites

A powder metallurgical production route was employed to produce Al-7.5 wt% Zn matrix composites reinforced with few-layered graphene (FLG). The in-house synthesized FLG by the electric arc discharge (EAD) method was incorporated into the Al-7.5Zn matrix through mechanical alloying (MA) in varying amounts (0, 0.5, 1.0, and 2.0 wt%). The mechanically alloyed (MAed) powders were consolidated by uniaxial pressing, and they were subjected to pressureless sintering at 635 °C for 2 h. The effects of FLG contents (0, 0.5, 1, and 2 wt%) and MA duration (0, 2, 4, and 8 h) were investigated regarding the microstructural, mechanical, tribological, and corrosion properties of bulk composites. The hardness values of 4 h MAed FLG/Al-7.5Zn composites having graphene in amounts of 0, 0.5, 1, and 2 wt% were determined as 77, 89, 107, and 119 HV, respectively. Compared to Al-7.5Zn alloy, 2 wt% FLG addition significantly increased the hardness of 4 h MAed Al-7.5Zn composites by approximately 54 %. In line with the hardness results, the addition of FLG notably and gradually enhanced the wear resistance of the composites. The Al-7.5Zn matrix displayed an ultimate compressive strength (σ_ucs) of 180 MPa, which significantly rose to 287 MPa for the Al-7.5Zn-1FLG composite, indicating a 1.6-times enhancement. Moreover, the addition of this amount of graphene did not degrade the corrosion performance of the Al-Zn matrix; in fact, it resulted in a slight improvement in the corrosion resistance of the composites.