چكيده به لاتين
Recently, magnesium (Mg) matrix composites have been considered widely by researchers and manufacturers due to its excellent strength to weigth ratio, low density of base metal and desirable machinability. Since Mg is one of the vital elements for human metabolism and has very similar mechanical properties to human bone, it can play a major role in orthopedic and medical applications. Among these features, Mg possesses a great biodegradability which is capable of being used as a biomaterial for manufacturing of ortheses and protheses and will eliminate secondary surgeries. Nevertheless, because of the high corrosion rate of Mg in biological environment, pure Mg cannot be used alone. To overcome this defect, using magnesium matrix composite is a reasonable solution and its corrosion resistance can be controlled. In this study, magnesium/hydroxyapatite bio-composite have been produced by magnetic-mechanical stirring method. Despite the importance of the fatigue behavior in the simulated body environment, no study has been done in this regard so far. Therefore, the corrosion fatigue behavior of the biocomposite is discussed. Also, the effect of stirring time on mechanical properties such as hardness, compression, tension and fatigue behavior have been investigated. It should be noted that the composite materials were prepared to examine the effect of the reinforcement phase with 2.5 wt% and 5 wt% hydroxyapatite and with different extrusion ratios of 1:5 and 1:20. The results indicate that 5 minutes of mechanical stirring along with the magnetic stirrer is considered as suitable mixing time. In general, the particles improve mechanical properties, corrosion resistance, fatigue behavior and in particular increase the fatigue life at the same stress amplitudes in comparison with pure Mg. The composite with 2.5 wt% hydroxyapatite showed better fatigue life than 5 wt% due to the reduction of corrosion rate.
