COMPARATIVE STUDY OF THE EFFECT OF SHOT PEENING TIME AND ANODIZATION SOLUTION ON FATIGUE STRENGTH AND CORROSION RESISTANCE OF MAGNESIUM ALLOY AZ91D FOR ORTHOPAEDIC IMPLANT APPLICATION

• Main Author: Antovie, Vanessa
• Format: Final Project
• Language: Indonesia
• Subjects: Metalurgi
• Online Access: https://digilib.itb.ac.id/gdl/view/51408
• Institution: Institut Teknologi Bandung

Magnesium has been reported to be the most biocompatible metal among all implant materials which have been used nowadays. However, fast and uncontrolled degradation, excessive production of hydrogen gas, and inadequate fatigue properties have fundamentally limited their application in biomedical field. Various solutions such as alloying, surface coating, and surface treatment have been put forward to enhance corrosion resistance of magnesium. However, many of these approaches can lead to a decrease in other characteristics, including biocompatibility. In this study, enhancement of fatigue strength and corrosion resistance of the magnesium alloys which has the best corrosion resistance, AZ91D, will be studied using the shot peening method and comparing it with anodization method. The variables investigated were the variation of shot peening time and the type of anodizing solutions and its concentration. This research was begun by doing a preliminary experiment in the form of shot peening with the time variations of 4 minutes, 7 minutes, and 10 minutes. Furthermore, hardness test was conducted using the Vickers Hardness Test method with load of 50 grams on the deformed surface. Then, the sample was characterized by using X-Ray Fluorescence (XRF) analysis. A critical review was also carried out by collecting data from research papers and books containing keywords AZ91D, magnesium alloys, shot peening, anodization, bioimplants, corrosion resistance, and fatigue properties. Some of the literatures was selected as the main literature. Then, data required from each major literature related to the variables to be analyzed were put together and an approach was made to analyze their effect on AZ91D alloys. From this critical review, conclusions and suggestions can be obtained for possible future experiments. From preliminary experiments and critical reviews, it is known that increasing shot peening time can enhance the fatigue resistance, hardness, and corrosion resistance of AZ91D. The existence of grain refining mechanism up to nano size particles, residual compressive stress, and surface defects such as twinning, slip, and stacking fault are the main keys to the mechanical properties and corrosion resistance improvement of AZ91D. However, the corrosion resistance of AZ91D is more dependent on the second phase, thus the improvement in corrosion resistance caused by shot peening is not too significant. Compared to the anodizing method, the shot peening method can be said to be more effective, because it does not only enhance the corrosion resistance, but also enhance the mechanical properties of AZ91D. It is also necessary to choose proper type of anodizing solution which safe for human body so that it does not cause other complications.