A variational approach to optimal open-loop ram velocity profiles for isothermal forging

This paper considers the problem of selecting the ram velocity profile in an isothermal forging, to best obtain a desired material microstructure. This is to be accomplished by tracking a prescribed strain rate profile. A weighting function, reflecting the rate at which the microstructure is transforming, describes the relative importance of different parts of the billet. Finding the optimal solution generally requires a search over an infinite-dimensional function space. However, for a certain class of forgings it can be approximated easily. The method is demonstrated for the simulated forging of a TiAl compressor disk