Project in the scope of the DFG Priority Programm 1676 Dry forming of aluminum alloys

Project in the scope of the DFG Priority Programm 1676 Dry forming of aluminum alloys: from fundamental material and surface characterization to new tribological systems

 

Motivation

The tendency to light weight construction causes high demands in all areas of the industry due to increasing environmental awareness and strict regulatory requirements concerning consumption of resources, carbon dioxide emission and waste removal. Metal forming is generally characterized by a high efficiency of material and energy consumption. Due to economic and ecological reasons the use of lubricants should become redundant. The forming of aluminum alloys makes high demands on forming processes. Aluminum alloys show a strong tendency of adhesion on common tool materials. The caused adhesions reduce the surface quality, the dimensional accuracy of the parts and the process stability. A high amount of lubricant is necessary to avoid the adhesion of the aluminum alloys. Up to now dry forming processes are not possible.

 
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[1] EDX-Map of an aluminum adhesion at an uncoated tool-surface (1.2379)

Aim

The adhesion behavior shall be examined by standard tribological testing equipment (rotating and oscillating pin on disk) as well as strip drawing tests. The mechanical, physical and surface properties of the used aluminum sheet metals and coatings shall be characterized before and after testing. The results of the characterization and the tribological tests will be the basis for a serious discussion of the adhesion mechanism. Finally, the correlations between the observed adhesion behavior and the influencing factors will allow the optimization of the tribological system concerning a real dry forming process, including the development of well adapted tool coatings.

Methodical approach

The main attention is focused on the adhesion behavior in dependency on the composition of the aluminum. Further attention will be given to the influence of different tool coatings based on different modified amorphous carbon coatings as well as the influence of different gaseous environments.