The effect of rolling temperature on the properties of biodegradable MG-0.7CA alloy for implant application

Abstract

Magnesium alloys as biodegradable implants have been introduced to the orthopedic and trauma surgery since past several centuries. Pure magnesium tended a large grain size and as a result of these phenomena will be weakening in mechanical properties. Consequently, by alloying the pure magnesium makes the material stronger instate of mechanical properties and it structure. In this present project, the effects of rolling temperature on properties of biodegradable Mg0.7Ca alloy were investigated. Alloy was cast by gravity die casting and rolled with five different temperatures 165ºC, 225ºC, 285ºC, 345ºC and 405ºC with reduction of 1mm, 2mm and 3mm. Microstructure of the sample was analyzed by optical and scanning electron microscope together with X-ray diffraction. To determine the mechanical properties, as-cast and as-rolled was through a tensile test and hardness test. As a result, the highest average maximum tensile stress was achieved at 345ºC that is 158 MPa and as-cast was 101MPa. However, by increasing the temperature and reduction gives a low hardness value. To determine the corrosion behavior of the alloy, electrochemical test was conducted on the sample in simulated body fluid. The result shows, by increasing the temperature of the rolling process support by reduction, were increasing the corrosion rate of some degree of the alloy. Although rolling process improved the strength, it does not satisfy the corrosion behavior of the alloy in implant application.