Abstract
Magnesium-based alloys as biodegradable orthopedic implants have been successful for their high degradation rates in the physiological environment and the consequent loss in the mechanical integrity. Casting method used in production of magnesium-based alloys influences the microstructure of implants due to cooling conditions. In this study, the effects of casting method (permanent mold casting and sand mold casting) on the degradation of AZ91D magnesium alloy in Hank's simulated body fluid at 36.5 ± 0.5°C have been investigated using immersion technique of cylindrical specimens. The specimens were subjected to simulated body fluid for 8 h and 24 h. The results have shown that the cooling rate from melt and grain size have great influence on the degradation rate of magnesium alloy.
Kurzfassung
Magnesiumlegierungen haben sich als erfolgreich bei der Verwendung als bio-degradierbare orthopädische Implantate aufgrund ihrer hohen Deradationsraten in physiologischen Umgebungen und ihrer damit verbundenen mechanischen Integrität erwiesen. Das Gießverfahren während der Produktion von Magnesiumlegierungen beeinflußt die Mikrostruktur solcher Implantate in Abhängigkeit von den jeweiligen Abkühlungsbedingungen. In der diesemBeitrag zugrunde liegenden Studie wurden die Einflüsse des Gießverfahrens (Kokillenguß und Sandguß) auf das Degradationsverhalten der Magensiumlegierung AZ91D in Hank's simulierter Körperflüssigkeit bei 36,5 ± 0.5°C mittels Tauchversuchen von zylindrischen Proben untersucht. Die Proben wurden der simulierten Körperflüssigkeit über 8 und 24 Stunden ausgesetzt. Die Ergebnisse haben gezeigt, dass die Abkühlrate der Schmelze und die Korngröße sich erheblich auf auf die Degradationsrate der Magnesiumlegierung auswirkt.
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