Effect of Extrusion on Microstructure and Mechanical Properties of MagnesiumBiodegradable Alloy (Mg-۴Y-۲Zn-۱Zr-۰.۶Ca)

Many researches have been done on the development of magnesium alloys for industrial and biomedicalapplications. Compared to other biodegradable alloys, Magnesium alloys have physical and mechanicalproperties such as density and Young’s modulus similar to body bone. Also, they have the ability tonaturally decompose due to being in an aqueous environment, which makes them useful forcardiovascular and orthopedic applications. One of the best methods for improving mechanical andcorrosion properties is extrusion. The impact of extrusion on microstructure and mechanical propertieswas investigated. analysis of microstructure and phases were studied by XRD, OM, SEM, and EDX.The results exhibited that equiaxed grains in all specimens and decreasing average grain size afterextrusion. Fine grains were formed in the microstructure as a result of the dynamic recrystallizationprocess during extrusion and besides structure, secondary phases in as-cast alloy composed of (α-Mg),(Mg۲۴Y۵), (Mg۳Y۲Zn۳) phases, and after homogenization, new phase (Ca۲Mg۶Zn۳) was formed; As thetemperature stability was in the range of ۳۴۹.۸ to ۳۹۹.۸ ̊c, thereby, this phase disappeared afterextrusion. The mechanical properties were improved due to grain refinement because during plasticdeformation, the density of dislocations increases, as a result, the strength of magnesium alloysimproves due to the resistance to movement of dislocations.

Keywords:

Magnesium alloy , Extrusion , Biodegradable , Biocompatible , Mechanical properties