Thixoforging - Basic experiment and optimized tool design

Thixoforging offers very complex forming possibilities. However, unlike thixocasting, a lot of work is still needed in this field. Numerous basic factors have to be developed for a better understanding of the process. The IBF has at is disposal numerical simulations, process data recording through corresponding basic experiments and a forming plant. A numerical simulation is very helpful for simulating the real process. Die fillings can be shown and optimized more quickly. All of this assumes a knowledge of the mass laws for the thixotropic behavior of metals. The idea of a mass law simulation, in which two different phases can be observed, will be presented in brief. Statements can thus be made on the flow behavior and thus the phase separation and segregation. If a simulation is to provide reliable results, certain process data has to be determined through tests. We will present the results of indentation tests in which the yield stress in the semi-solid state is made measurable. Important parameters for thixoforging will be compiled in a process map. A new test concept will be presented to determine these parameters, such as temperature, liquid share and flow rate. Special consideration will hereby be paid to the biphase state of the metal and this will be incorporated into the FEM. The process sequence in thixoforming (thixoforging and casting) can be divided up into feedstock material manufacturing, heating and forming. Results of feedstock material manufacturing, the heat treatment of thixoforged components and a new tool concept will be presented at the end of the report.