Abstract
Magnesium alloys have poor ductility and it is difficult to manufacture magnesium alloy parts at room temperature. In this study, to form magnesium alloy sheets without heating using energy sources such as furnaces, torches and laser beams, a new forming process, called the friction stir incremental forming process, was developed. AZ31-O magnesium alloy sheets of 0.5mm thickness were formed into a frustum of pyramid shape. Tool rotation rate, tool feed rate, and the half apex angle of the pyramid were changed. Not only microstructure observation but also the investigation of formability was carried out. Formability by the developed method was compared with that by the conventional hot incremental forming method. From the experimental results, the AZ31 sheet of 0.5mm thickness was formed into a frustum of pyramid shape with a minimum half apex angle of 25° by the developed method and the sheet showed 137% elongation at room temperature. The degree of springback decreased when suitable working conditions were employed. The formability by the developed method was higher than that by the conventional hot incremental forming method.
