Developing Empirical Relationship to Predict Corrosion Rate of High Strength AA 7075-T651 Aluminium Alloy Under Salt Fog Environment
1MANUFACTURING ENGINEERING, ANNAMALAI UNIVERSITY, CHIDAMBARAM, TAMILNADU, India
2MECHANICAL ENGINEERING, SSN College of Engineering, CHENNAI, TAMILNADU, India
*Email Address : srkcemajor@yahoo.com
Abstract : The aluminum-zinc alloy system is very attractive to the aerospace industry due to its lower density, increased elastic modulus, increased fatigue crack growth resistance, easy formability and strength to weight ratio. As a consequence, this light alloy has shows potential future. However, these alloys have great affinity for chloride environment and other chemical oxidizing agents. The limitation of low corrosion resistance restricts their practical applications. The rolled AA7075-T651 plates were evaluated by conducting salt fog test in NaCl solution at different chloride ion concentrations, pH value and spraying time. Also an attempt was made to develop an empirical relationship to predict the corrosion rate of AA7075-T651 high strength Al alloy. Three factors five level of central composite design were used to minimize the number of experimental conditions. Response surface method was used to develop their empirical relationship. The developed relationship can be effectively used to predict the corrosion rate of AA7075-T651 at 95% confidence level.
Keywords : AA7075-T651,Microstructure,Salt Fog Corrosion,Response Surface Methodolog