Microstructure based strengthening model of a biocompatible WE54 alloy reinforced by SiC.

A large number of magnesium alloys and magnesium-based composites are nowadays used as biocompatible light metallic materials. Example of their applications include bone-tissue screws, cardiac valves, orthodontic screws and components. In this sense, the biocompatibility, durability, and corrosion resistance and blood compatibility are key factors for the full availability of magnesium based alloys in the bioengineering field. On the other hand, minimal necessary mechanical properties necessary for their potential application in such a filed were investigated in the last three decades. With this respect, not only magnesium based alloys, but also magnesium composite alloys were tested for their biocompatibility. Oxides such TiO2, MgO, ZnO, ZrO2, TiB2, Al2O3, and also SiC showed sufficient biocompatibility and in addition, composite magnesium alloys added with such oxides or SiC are known to possess higher mechanical properties compared to their magnesium alloy counterparts. Among the different available metallurgical technologies to produce magnesium alloys, the powder metallurgy (PM) is surely one of the most promising one. With this regard, squeeze casting is one of the most reliable and cost-effective PM technique of production of magnesium based alloys and composites. In the present work, the microstructure and mechanical properties of WE54+15vol.%SiC under various compression temperature conditions, up to 300°C, were investigated by transmission electron microscopy (TEM). Microstructure inspections revealed the formation of stable cuboid secondary phase particles, and lamellae and irregular-shaped intermetallic phases. A microstructure-based strengthening model was proposed and compared to the experimentally obtained compression stress carried out at temperatures ranging 50-to-300°C. The most effective strengthening term was found to be the one coming from the refined grain structure. A further important strengthening contribution was constituted by the secondary phase particle precipitation within the Mg-matrix