Effect of Reinforcing Additive Nanoparticles on the Mechanical Properties and Microstructures of AZ31 Composites Processed by Severe Plastic Deformation
Abstract:
Knowing and developing new materials is necessary to meet the growing needs of industries. Magnesium-based composites are one of the metal-based composites that have received attention due to having some special properties. Magnesium and its alloys have favorable characteristics such as light weight, good strength and biocompatibility. Adding reinforcing particles to the magnesium field improves some mechanical and chemical properties. Graphene reinforcement nanoparticles, which are from the family of ceramic and carbon reinforcements, have received much attention in recent years. On the other hand, the use of severe plastic deformation processes changes the microstructure of the material to a great extent and causes the modification of the mechanical and chemical properties of the material. In this research, AZ31 magnesium alloy reinforced with graphene nanoplates (GNPs) and reduced graphene oxide nanoplates (RGO) was produced using the spark plasma sintering (SPS) method. In this research, AZ31 magnesium alloy reinforced with graphene nanoplates (GNPs) and reduced graphene oxide nanoplates (RGO) was produced using the spark plasma sintering (SPS) method. The closed die forging process has been carried out at ambient temperature and 375°C in order to achieve improved mechanical properties. By performing one pass of the process, microstructure modification, more homogeneous structure formation, increased hardness and final tensile strength were achieved. So that the hardness of the samples reinforced with graphene nanoparticles after forging at ambient temperature and after hot forging increased by 21% and 24%, respectively. In addition, in the samples reinforced with reduced graphene oxide nanosheets compared to the pure sample, a 13% increase in final strength after forging at ambient temperature and an 18.5% increase after hot forging were observed. Also, the grain size decreased from 114 µm to 36.5 µm after forging at ambient temperature and to 35.2 µm after hot forging. Likewise, the hardness of the samples reinforced with graphene nanoplates (GNPs) increased by 24% compared to the pure sample, from 63.94 Vickers to 79.26 Vickers. In addition, the hardness of samples reinforced with reduced graphene oxide (RGO) nanosheets was obtained as 43.74 Vickers. Biocompatibility tests were performed by immersing the produced samples in SBF solution. The results showed an increase in the absorption percentage of calcium to phosphorus in AZ31/RGO samples by 76.1 and in AZ31/GNPS samples by 54.1.