Corrosion Behavior of Engineering Materials in Flow Field Yuki Soya 1, a , Shoichiro Yoshihara 1,b , Yuki Ohmura 1,c , Bryan J. MacDonald 2,d and Emmet Galvin 2,e 1 University of Yamanashi, 4-3-11 Takeda, Kofu-city, Japan 2 Dublin City University, Collins Ave, Dublin 9, Ireland a g13mm016@yamanashi.ac.jp, b yoshihara@yamanashi.ac.jp, c g13mm009@yamanashi.ac.jp, d bryan.macdonald@dcu.ie, e emmet.galvin3@mail.dcu.ie Keywords: Corrosion behavior, AZ31 Magnesium alloy, Bioabsorbable materials, Flow field, Simulated body fluid. Abstract. In this study, the effect of fluid flow rate, surface roughness and strain level on the corrosion behavior of magnesium alloy AZ31 was characterized in a custom test bench. Specimens were prepared by mechanical polishing and subject to flow in a simulated body fluid at 37°C for 24 hrs. Compared to a specimen pre-strain of 0%, mass loss was shown to increase by approximately 6% with a specimen pre-strain of 10%. Similarly, mass loss increased by approximately 13% when the fluid flow rate was increased from 250ml/min to 500ml/min. Surface roughness had a significant influence on corrosion behavior. Compared to a specimen polished with a 1 μm diamond paste, the mass loss for a specimen polished with #600 sandpaper was 28% greater. Introduction Recently, the application of bioabsorbable materials in medical implants has increased. Magnesium alloys are biocompatible and can be absorbed inside the body. Magnesium is an essential element in the body and is efficiently excreted by the kidneys. Therefore, much research has focused on using magnesium alloys as implant materials and devices such as bioabsorbable stents. Many contemporary stents are manufactured from stainless steel (316L) which has high corrosion resistance and remains as a permanent implant in the body. This has many limitations including chronic irritation and the release of toxic substances. Magnesium alloys stents can overcome many of these limitations as the device is absorbed into the body. In patients with coronary artery disease, magnesium alloy stents can be deployed at the site of a stenosis in order to temporarily scaffold the diseased vessel. In some cases, after a period of 6-9 months the vessel has remodeled and the device is no longer required. Therefore, much research into magnesium materials has focused on controlling the corrosion rate so that the biocorrosion of the device can be tailored to the specific anatomical site [1]. The in vitro corrosion behavior of magnesium alloys is affected by many factors such as mechanical strain, temperature, surface area and solution transport conditions (e.g. flow rate). A number of studies have examined the in vitro corrosion behavior of magnesium alloys and devices [2]. The corrosion behavior of three types of AZ91 magnesium alloy with various weight percentages of calcium was examined using electrochemical techniques and surface analyses [3]. The effect of polished surface conditions, geometrical characteristics of the exposed area and different aluminum contents on the corrosion behavior of magnesium alloys (AZ31 and AZ61) was investigated [4]. The die-cast AZ91D and extruded WE43 alloys were chosen to evaluated their fatigue and corrosion fatigue behaviors in simulated body fluid [5]. In a Chandler-Loop model, the initial degradation of eight different magnesium alloys during 6 h in contact with human whole blood was investigated [6]. The corrosion behavior of AZ31 magnesium alloy with different grain sizes immersed in simulated body fluids was compared in chloride solution and in phosphate-buffer solution (PBS) [7]. Also magnesium alloys stent studies was carried out. The study for comparing Advanced Materials Research Vol. 922 (2014) pp 722-727 © (2014) Trans Tech Publications, Switzerland doi:10.4028/www.scientific.net/AMR.922.722 All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP, www.ttp.net. (ID: 136.206.98.233-28/04/14,11:43:47)