Tribological behavior of AZ91D magnesium alloy composite: effect of hybrid WC – SiO2 nanoparticles

Purpose Aviation field requires a material with greater tribological characteristics to withstand the critical climate conditions. Hence, it is of paramount importance to enhance the wear resistance of material. AZ91D magnesium alloy is a light weight material used in the aviation field for the construction work. The purpose of this study is to augment the wear properties of AZ91D alloy by reinforcing with hard particles such as tungsten carbide (WC) and silicon dioxide (SiO2). Design/methodology/approach In this work, three types of composites were fabricated, namely, AZ91D – WC, AZ91D – SiO2 and AZ91D – (WC + SiO2) by ball milling method, and the tribological properties were analyzed using pin-on-disc apparatus. Findings Results showed that the hardness of AZ91D alloy was greatly improved due to the reinforcing effects of WC and SiO2 particles. Wear study showed that wear rate of AZ91D alloy and its composites increased with the increase of applied load due to ploughing effect and decreased with the increase of sliding speed owing to the formation of lubricating tribolayer. Further, the AZ91D – (WC + SiO2) composite exhibited the lower wear rate of 0.0017 mm3/m and minimum coefficient of friction of 0.33 at a load of 10 N and a sliding speed of 150 mm/s due to the inclusion of hybrid WC and SiO2 particles. Hence, the proposed AZ91D – (WC + SiO2) composite could be a suitable candidate to be used in the aviation applications. Originality/value This work is original which deals with the effect of hybrid particles, i.e. WC and SiO2 on the wear performance of the AZ91D magnesium alloy composites. The literature review showed that none of the studies focused on the reinforcement of AZ91D alloy by the combination of carbide and metal oxide particles as used in this investigation.

Tribological and ageing behavior of Az91D magnesium alloy fortified with nano lanthanum and nanoceria by stir casting for aviation application

Purpose The aviation field requires a material with the ability to withstand severe environmental conditions. The purpose of this paper is to provide higher wear resistance and improve the lifetime of aircraft. Hence, it is vital to enhance the wear resistance and strength of the material. Design/methodology/approach In this investigation, the Az91D magnesium alloy was reinforced with lanthanum (La2O3) and cerium oxide (CeO2) nanoparticles by stir casting and heat treatment process and the tribological and mechanical properties were analyzed. Findings The results showed the Az91D/CeO2 composite exhibited higher density (1.96 g/cm3) and lower porosity (1.01%) compared to other materials due to the diffusion of CeO2 nanoparticles in between the atoms of Az91D alloy. The hardness of Az91D/ CeO2 & Az91D/ La2O3 was improved by 38% and 34%, respectively, compared to Az91D alloy owing to the reinforcing effect of hard nanoparticles. Further, the inclusion of nanoparticles decreased the mass loss and showed lower wear rate compared to the Az91D alloy due to the pinning effect of nanoparticles. In addition, the friction coefficient was observed in the order of Az91D > Az91D/ La2O3 > Az91D/ CeO2. Moreover, the heat treatment displayed positive results on the properties of all the materials. Originality/value This work is original as the combination of cerium oxide nanoparticles with Az91D magnesium alloy is not tried by earlier investigators. Further, the comparative performance of both lanthanum and cerium oxide nanoparticles on the tribological and mechanical behavior of Az91D alloy has been analyzed for aviation application. This study will provide new information to the scientific world to increase the lifetime of aviation structures.