Effect of heat treatment on fatigue behavior and mechanical properties of Al 7021-T6

Abstract

Al 7021 alloy is offered for the automotive bumper and airplane industry. Having strength comparable to many high-strength low-alloy steels, 7021 alloy can give a 63% weight saving in the beam applications. The effect of heat treatment on the rotating beam fatigue strength of age-hardened 7021-T6 aluminum has been investigated. The high cycle fatigue tests (HCF), resistance of such alloy at room temperature under fully reversed bending loading was investigated for frequency of 50 Hz. Fatigue testing was conducted on smooth round bar (S-N) specimens. For Solution heat-treated and then artificially aged 7021-T6, compared to basic alloy, observed improvements were about 33% for Al 7021-T6 in fatigue behaviour after heat treatment. Microstructure, hardness, and other mechanical properties were conducted to Al 7021 before and after heat treatment. It was found that heat treatment can dramatically enhance the fatigue behavior of aluminum alloys as compared to the extruded alloys.