Microstructural properties and mechanical behavior of magnesium/hydroxyapatite biocomposite under static and high cycle fatigue loading

Abstract

In this study, magnesium/hydroxyapatite biocomposites having 2.5 and 5 wt% of hydroxyapatite have been fabricated using stir casting followed by hot extrusion method. Both microstructural and mechanical behaviors of these composites have been studied, which contain particle distribution, grain size, microhardness, tension, and compression tests. Then, high cycle fatigue tests were performed using a rotating-bending testing machine (under stress ratio of R = −1). The results indicate an acceptable particle distribution and grain refinement in the composites. Also, the microhardness of the composites has been increased in comparison with the pure extruded sample. The yield stress has been enhanced in both tension and compression tests by increasing the amount of reinforcement, while the maximum strain reduced. Moreover, the fabricated biocomposites revealed better overall high cycle fatigue life in comparison to pure Mg, and infinite life (>107 cycles) could be achieved in the composites. Scanning electron microscope images of the fracture surfaces showed that the agglomeration of hydroxyapatite particles is one of the most important criteria for crack initiation in the composites.

Corrosion fatigue behaviour of electrospun PCL/HA coated magnesium biocomposites

“…It is calculated that the final strain is 0.21 with a slight reduction of 3%. Other studies have indicated similar results for compressive properties in terms of reduction and increase [52,53].…”

“…Khanra et al [52] reported a rise in tensile yield strength, ultimate tensile strength, and a decrease in maximum strain by adding 5% HA (particle size of 1 to 5 µm) to the ZM61 matrix using a similar method. With the addition of 2.5% HA (average particle size of 600 nm), Sabet et al [53] presented an amplification in yield stress, a decrease in ultimate tensile strength, and a diminution in maximum strain. According to Figure 6(b), the compressive yield strength is augmented by 159% to 153 MPa, and the ultimate compressive strength is enhanced by 16% to 374 MPa.…”

Magnesium-Based Bioactive Composites Processed at Room Temperature

“…There are many reports on the fabrication of magnesium-based composites with hydroxyapatite using not only commercial purity Mg (CP-Mg) [12,13,14,15,16,17,18], but also Mg alloys such as AZ91 (Mg-9 wt% Al-1 wt% Zn) [19,20]. The usual fabrication methods involve heating, such as sintering [12,16,17] or hot extrusion [15,18,19,21]. The addition of HA within the Mg matrix, combined with mechanical processing, provides both grain refinement and a gain in strength.…”

Mechanical and microstructural properties of titanium/hydroxyapatite functionally graded material fabricated by spark plasma sintering

“…Although it is most widely used for implants, researchers recently tend to combine the titanium whit dental ceramics to improve the implants mechanical and biological properties. Hydroxyapatite (HA) is a bioceramic having excellent biocompatibility for medical applications [11]. Moreover, HA as the main component of bone and teeth has bioactive properties for new bone formation [12].…”