Optimum Load in Vickers Microhardness Testing of Treated Magnesium Alloy by Thermal Oxidation

Magnesium and its alloy have good properties as biomedical implant such as biodegradable material and excellent biocompatibility. Their hardness is an important mechanical property in using of these materials. Vickers microhardness is one of hardness testing methods in metal materials especially for thin layer on the metal. Mass of microhardness testing load also has important effect on result validity. The object of this research is to investigate optimum load in Vickers microhardness testing of magnesium alloy treated by thermal oxidation. Magnesium alloy AZ61 was treated by annealing at 150; 225; 300; 375; 450 °C of temperature. Vickers microhardness testing was carried out on this treated material using 5, 10, 25, 50, and 100 g of load. Five data for both each load and temperature, therefore there are 25 data for each load. Optimum load is determined the load which has lowest standard deviation in Vickers microhardness. The optimum load in this research was happened at 10 g in load of Vickers microhardness testing. The Vickers microhardness in this load was 36.0 g.mm -2 and the standard deviation was 2.7 g.mm -2 .