Investigating the effects of hard anodizing parameters on surface hardness of hard anodized aerospace AL7075-T6 alloy using fuzzy logic approach for fretting fatigue application

Abstract

Aerospace applications and energy saving strate- gies in general raised the interest and study in the field of lightweight materials, especially on aluminum alloys. Alumi- num alloy itself does not have suitable wear resistance. There- fore, improvements of surface properties are required in practical applications, especially surface hardness when alu- minum is in contact with other parts. In this work, first Al7075-T6 was coated using hard anodizing technique in different parameters condition and the surfaces hardness of hard anodizing-coated specimens were measured us- ing microhardness machine. Second, fretting fatigue life of AL7075-T6 was investigated for both uncoated and hard anodized specimens at the highest surface hardness obtained. Third, a fuzzy logic model was established to investigate the effect of hard anodizing parameters, volt- age, temperature, solution concentration, and time on the anodized AL7075-T6. Four fuzzy membership func- tions are allocated to be connected with each input of the model. The results achieved via fuzzy logic model were verified and compared with the experimental re- sult. The result demonstrated settlement between the fuzzy model and experimental results with 95.032 % accuracy. The hardness of hard anodizing-coated speci- mens was increased up to 360 HV, while the hardness of uncoated specimens was 170 HV. The result shows that hard anodizing improved the fretting fatigue life of AL7075-T6 alloy 44 % in low-cycle fatigue.