Fatigue Life Estimation of TIG Welded Aluminum Alloy (Aa2219) Under Combined Loading

Fatigue life of structural components is greatly influenced by increase in temperature. It is therefore important to study the behavior of materials under Combined Thermal Cycling (CTC). Components and parts made from aluminum are subjected to cyclic loading under high operational temperatures; hence it is necessary to determine fatigue behavior of aluminum alloys under such conditions. In this study crack initiation and fatigue life of aluminum alloy is investigated under four point rotating bending fatigue test at high temperature. CTC and notch geometry effects were also investigated in this study. High temperature testing fixture was developed and installed on the machine to carry out tests at higher temperatures. S-N curves obtained in this study shows that the fatigue life of subjected aluminum alloy is low at higher temperatures. A detailed investigation on microstructure was also made and used to show harmonious experimental results.