Estimation of fracture toughness (KIC) using Charpy impact test for Al6061T6 and Al7075T6 alloys subjected to corrosion

Fracture Toughness (KIC) is an important material property in fracture mechanics. There are numerous literatures that suggest the use of relationship between the fracture toughness (KIC) and impact strength (CVN). In this investigation, the relationship between KIC and CVN was used to determine the fracture toughness of high strength, low density Al6061T6 and Al7075T6 aluminum alloys. Accelerated corrosion was performed on these alloys using salt spray in a closed chamber for 250 h and 500 h. Pitting corrosion followed with exfoliation corrosion was noticed after prolonged exposure time which were responsible for the deterioration of mechanical properties. The experimentation results in degradation of yield strength, tensile strength, and impact strength with increase in exposure time. The yield and the impact test results were considered to estimate fracture toughness using the relations proposed by Rolfe and Barsom, Weld Research Council (WRC) and Robert and Newton. The KIC results were validated analytically using Compact Tension (CT) and Single Edge Notched Bend (SENB) specimens. The results show that, KIC decreases with increase in exposure time for all the combinations considered. Further, it was relatively observed that Al7075T6 is more susceptible to corrosion than Al6061T6. (c) 2021 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Smart and Sustainable Developments in Materials, Manufacturing and Energy Engineering.