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A prediction model for cold flow curves was introduced for a new class of composite materials known as TRIP-matrix-composites consisting of three phases, austenite, strain-induced martensite and ZrO2. The content of the ceramic phase was varied between 0 and 30%, whereas the particle size of the ceramic was selected to be 10 to 30 μm. For the manufacturing of the composite material the powder metallurgical route including hot press procedure was chosen and very dense material could be produced.Included in the model is the hydrostatic stress σm close to the circumferential surface of the compression test sample. The hydrostatic stress was varied using different material compositions and true strain values. To calculate the cold flow curves the ISO-E-method was applied. The calculated results show a consistent congruency with the experimental data.

In the present work, a new method to predict the stress-strain curves for three-phase materials has been developed. It was applied using the example of an Mg-stabilized zirconia reinforced TRIP-matrix-composite. The content of the ceramic phase was varied between 5% and 20%, whereas the particle size of the ceramic was selected to be 30 to 50 µm. The method is a further development of mixture rule for multiphase materials with more than two microstructure components. The prediction results were compared with the original method of mixture rule and with the IsoE-method. It is shown that the new method significantly improves the convergence compared to the standard method for mixture rule, even though it does not reach the accuracy of IsoE-method. Furthermore, there is an improvement of predicted convergence for large values of the total stress. Finally, a working map was designed for a quick graphical definition of the objective functions.

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The present technical work reports on the formability and related behaviour of components during hot rolling of metal matrix composites (MMC) produced from powder. A new metal matrix composite based on TRIP (Transformation Induced Plasticity) austenitic steel AISI304 with varying amounts (10% and 20%) of homogeneously embedded zirconium dioxide (partially stabilized with Mg (Mg-PSZ)) was investigated by means of compression tests and rolling of wedge shaped samples at temperature of 900°C and 1100°C. Two different particle size distributions of Mg-PSZ powder were investigated: fine and coarse. Based on the experimental results, the deformation behaviour (arc of contact length, roll gap ratio, strain, strain rate), the microstructure evaluation (pore amount and their cross sectional area) and the formability (equivalent fracture strain) under different stress state conditions had been analyzed.