Microstructural basis for improved corrosion resistance and mechanical properties of fabricated ultra-fine grained Mg-Akermanite composites

In the present research, a composite with a magnesium alloy (WE43) as the matrix and Akermanite as the bioactive and reinforcing agent was fabricated by friction stir processing (FSP), resulting in a microstructure with uniformly distributed fine grains, second-phase particles and micro-sized Akermanite particles. The effect of an addition of...

Extrusion-based additive manufacturing of Mg-Zn/bioceramic composite scaffolds

The treatment of femoral nonunion with large segmental bone defect is still challenging. Although magnesium alloys have been considered potential materials for such a treatment, their application is limited by their fast degradation. Adding bioceramic particles into magnesium to form Mg-matrix composites is a promising strategy to adjust...

Simulation of deformation and fracture initiation during equal channel angular pressing of AZ31 magnesium alloy with covered tube casing

The present research was aimed at lowering the deformation temperature by applying cover tube casing (CTC) to AZ31 magnesium alloy samples subjected to equal channel angular pressing (ECAP) without triggering surface defects and/or fracture. The Cockcroft-Latham (C & L) fracture model was incorporated into finite element simulation and...

Applying multi-pass friction stir processing to refine the microstructure and enhance the strength, ductility and corrosion resistance of WE43 magnesium alloy

Magnesium alloys have many unique properties, mostly benefitting from the low density of magnesium. However, they are not competitive, when compared with other lightweight materials, such as aluminum alloys, particularly in ductility and corrosion resistance. There is a strong need to improve the mechanical properties and corrosion resistance...

An experimental and theoretical investigation of the effect of second-phase particles on grain growth during the annealing of hot-rolled AZ61 magnesium alloy

The mechanical properties of a magnesium alloy strongly depend on its grain structure. It is desirable to minimize grain growth during the post-forming annealing treatment, thereby minimizing the loss in strength while regaining ductility. In the present research, the annealing of the hot-rolled AZ61 Mg alloy at different temperatures for...

The effect of addition of hardystonite on the strength, ductility and corrosion resistance of WE43 magnesium alloy

A composite material based on the WE43 magnesium alloy and containing nano-sized hardystonite ceramic particles was processed by means of friction stir processing (FSP). Compressive strength and strain-at-failure of the WE43 alloy increased as a combined result of FSP and nanoparticle reinforcement. The results of potentiondynamic...

Corrosion resistance and tribological behavior of ZK30 magnesium alloy coated by plasma electrolytic oxidation

The rapid bio-corrosion of magnesium-based alloys, the formation of hydrogen gas and, consequently, the premature loss of biomechanical functions hinder their applications as biodegradable implant materials. The corrosion becomes even accelerated, when fretting wear occurs at implant junctions, as a result of repeated disruptions of the...

Construction of three-dimensional extrusion limit diagram for magnesium alloy using artificial neural network and its validation

Conventional extrusion limit diagram (ELD) involves only two extrusion process variables and as such it does not account for the combined effects of multiple process parameters on the extrusion process with respect to pressure requirement and extrudate temperature. Attempts were made in the present research to construct three-dimensional (3D)...

Solvent-cast 3D printing of magnesium scaffolds

Biodegradable porous magnesium (Mg) scaffolds are promising for application in the regeneration of critical-sized bone defects. Although additive manufacturing (AM) carries the promise of offering unique opportunities to fabricate porous Mg scaffolds, current attempts to apply the AM approach to fabricating Mg scaffolds have encountered some...

Biodegradation and mechanical behavior of an advanced bioceramic-containing Mg matrix composite synthesized through in-situ solid-state oxidation

Recent studies have shown great potential of Mg matrix composites for biodegradable orthopedic devices. However, the poor structural integrity of these composites, which results in excessive localized corrosion and premature mechanical failure, has hindered their widespread applications. In this research, an in-situ Powder Metallurgy (PM)...

Improvement of mechanical performance of bioresorbable magnesium alloy coronary artery stents through stent pattern redesign

Optimized stent pattern design can effectively enhance the mechanical performance of magnesium alloy stents by adjusting strain distribution and evolution during stent deformation, thereby overcoming the limitations imposed by the intrinsic mechanical properties of magnesium alloys. In the present study, a new stent design pattern for...

Advanced bredigite-containing magnesium-matrix composites for biodegradable bone implant applications

The present research was aimed at developing magnesium-matrix composites that could allow effective control over their physiochemical and mechanical responses when in contact with physiological solutions. A biodegradable, bioactive ceramic - bredigite was chosen as the reinforcing phase in the composites, based on the hypothesis that the...