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

Abstract

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.

Variasi Rapat Arus Terhadap Sifat Mekanik Dan Morfologi Lapisan Magnesium Az31 Dengan Menggunakan Metode Electrophoretic Deposition (Epd)

“…Faktor internal yang mempengaruhi ketahanan korosi pada logam yaitu struktur mikro, regangan, dan kekerasan permukaan. Proses coating dapat mengubah sifat mekanik, perubahan kekerasan terjadi pada permukaan atas ke bawah bagian dalam [6,7]. Pengujian kekerasan Vikers adalah metode umum yang digunakan untuk mengevaluasi kekerasan material, termasuk paduan magnesium.Pengingkatan kekerasan Vikers berhubungan dengan dosis ion, variasi parameter kisi, dan ukuran kristal [8].Variasi rapat arus yang dilakukan 0.005 A/mm 2 , 0.0075 A/mm 2 , and 0.01 A/mm 2 , karena rapat arus yang terlalu rendah tidak mampu membentuk lapisan sedangkan rapat arus yang terlalu tinggi menyebabkan lapisan tidak melekat erat dan rapuh [9].…”