Investigation into the strength of components made of UFG aluminium alloys

Aluminium is a very important light metal used in nearly all fields of engineering. Several high strength alloys are available, especially alloys of the EN AW-6XXX- and 7XXX-type. In spite of the fact that these alloys are suitable for heat treatment in order to reach minimum ultimate tensile strength of 310 MPa for EN AW-6082 and 560 MPa for EN AW-7075 respectively there is the need to improve several material properties like ultimate strain or corrosion resistance. A possible way to optimize the mechanical properties is the modification of material structure into an ultrafine-grained one, so called UFG-structure. The content of this paper is divided into two parts. Firstly, mechanical properties of bolts, made of common material as well as UFG-structured material are investigated. Secondly, FE-calculations of bolts including detailed thread are presented as a step for further optimization of fastener design. Results regarding mechanical properties of bar specimens made of UFG-aluminum alloys were already published. The aim of this paper is to prove the mechanical properties of bolts as an example of real engineering components. The main objective is the investigation into the strength and stress distribution on aluminium bolts made of EN AW-6082T6 and EN AW-7075T6 with thread M6. The bolts were tested in static tensile tests and in fatigue tests