Characterization of residual stresses and mechanical performance of gas tungsten arc welded aluminum alloy 6061-T6

Abstract

The use of aluminum welding is used in everyday applications anywhere from manufacturing small brackets to commercial airliner fittings to household ladders. Due to its light weight and resistance to corrosion, aluminum has become one of the leading materials used on projects where steel or other high strength materials are out of the question. The fusion of aluminum parts by means of welding is a complex process and takes a very skilled welder to make sure the integrity of the material is not susceptible to failure in its environment. Different studies have taken place on welded aluminum, in particular, type Al 6061-T6, to test whether this alloy meets the standard requirements for wherever it is being used. Researchers have conducted numerous experiments quantifying the hardness and tensile strength of the weld area, however there is very little done on time dependent trials other than hardness testing. Because welded AA 6061-T6 ages naturally over the first month after welding, these changes must be accounted for in other areas of interest, such as static and dynamic loading conditions. Various welding techniques bring different outcomes to the mechanical properties of aluminum. Both static and dynamic testing is required to fully describe and understand the properties that welded structures take. Time dependent tensile testing and impact testing on and near the weld are two tests that satisfy this necessity to understand what stresses and forces the material can withstand during and after the initial stages of natural ageing. Residual stress measurements and hardness testing were also performed in this research to gain a better understanding of how welding effects sheet metal aluminum.