Developing magnesium-based composites through high-pressure torsion

Abstract

Magnesium and its alloys display interesting properties such as low density and biocompatibility but the lack of ductility and low strength compromise their performance in many applications. Fabrication of metal matrix composites may alleviate these challenges and improve overall performance. Magnesium matrix composites can be produced by cold consolidation of particles through high-pressure torsion and this paper summarizes recent findings in processing routes for the fabrication of composites, the microstructure developed, mechanical properties obtained and potential applications. It is shown that ductile materials can be mixed with magnesium by processing half samples placed side by side and hard and brittle materials can be incorporated by processing mixed particles. The distribution of phases may be controlled by the amount of rotation imposed during processing. Well-dispersed second phase particles within a continuous magnesium matrix can be obtained. Thus, it is possible to incorporate bioactive materials within a biodegradable magnesium matrix. Detailed characterization using transmission electron microscopy reveals the processing also refines the grain structure of the metallic matrix. The composites may display good ductility, improved strength and an ability to precipitate intermetallics through thermal treatment. The composites produced using high-pressure torsion have different potential applications including the development of bioactive and biodegradable biological implants.

Corrosion Behavior in Hank's Solution of a Magnesium–Hydroxyapatite Composite Processed by High‐Pressure Torsion

“…It was shown earlier that HPT processing is able to consolidate Mg particles with the addition of HA particles to produce an Mg-HA composite. [27] These results confirm the formation of such composite and show that there are well-distributed HA particles embedded within an Mg matrix. In addition to the room temperature consolidation of this composite, HPT processing also significantly refines the grain structure of the Mg matrix and produces an ultrafine-grained structure.…”

Fabrication of Magnesium-Aluminum Composites under High-Pressure Torsion: Atomistic Simulation

“…One of the possible ways to obtain metallic composites is high-pressure torsion (HPT), during which high compressive and shear stresses result in the formation of the composite structures. To date, several types of composite materials were obtained by HPT from metallic plates: Al-Cu [7][8][9][10][11][12][13], Al-Mg [14][15][16], Al-Nb [17], and Al-Ti [18]. Since severe plastic deformation can increase the diffusion in the materials [19,20], in situ composites can be obtained by HPT through the bonding of different metals, which can lead to the formation of new intermetallic phases.…”