Selective Strain Hardening of Structure Components by Action Media Based Cold Massive Forming
High strength aluminium wrought alloys as well as powder metallurgical aluminium alloys are limited regarding massive formability. The formability at room temperature can be significantly affected by superimposing hydrostatic pressure. Depending on the process control, cold forming enables locally induced strain hardening effects, whereby increased hardness or hardness gradients can be regulated. Simultaneously, the necessity of mechanical post processing is reduced by a metal forming fabrication of joint and connection elements at room temperature. By splitting the component in strengthened and not strengthened regions, specially adapted property profiles can be adjusted to the application. Thus, specially load adapted components with locally optimised property profiles e.g. ductile or high strength, brittle areas can be manufactured. A defined buckling or folding of a component in case of a crash can thereby be achieved. In this project innovative tool principles for superimposed cold solid forming will be developed. They will be used to manufacture high strength and complex aluminium structure components with specific adjustment of local strain hardening. A tool technique is to be created in order to generate locally hardened areas within massive structures by metal forming. Furthermore, the task is to determine the procedures limits for superimposed cold massive forming with specifically adjusted strain hardening of aluminium alloys. For the realisation of these aims fundamental research has to be made, by which the coherences between specific process parameters and the increased formability are determined. Furthermore, the cold hardening effects are to be adjusted by cold massive forming with superimposed hydrostatic pressure and displayed with the help of FEA. In the long term, the analysis aims at the development of pressure superimposed forming that is technically utilisable as a near net shape manufacturing process for high complex aluminium structure components with selective adjustment of local properties.
Heinz Palkowski and Kai-Michael Rudolph
B. A. Behrens et al., "Selective Strain Hardening of Structure Components by Action Media Based Cold Massive Forming ", Advanced Materials Research, Vol. 22, pp. 57-65, 2007