Pressure Profile Optimization on a Superplastic Aluminium Alloy

In this work authors present a study of the influence of the pressure profile on forming time and on post-forming characteristics of superplastically formed parts. Material parameters of an aluminium superplastic alloy (ALNOVI-U) were estimated on the basis of experimental tests and of a numerical approach. A numerical model of the forming process was then created and used for evaluating the pressure profile able to keep the maximum strain rate value close to a target value. Pressure profiles were calculated using a strain rate control algorithm, firstly following a conventional approach and monitoring the whole sheet, and then considering only the elements most deformed at the end of the forming process. Experimental results from different numerical pressure profiles are then compared, in terms post-forming characteristics, to test the effectiveness of the approach.