For the development of new materials, Fraunhofer-Center HTL always places the focus on the planned application for the customer. Using the required application properties, a specific catalogue of thermal, mechanical, electrical and chemical properties, which must be satisfied in the material design, is compiled. The processing steps on the way from the raw material to the finished product often set further limitations, which must be taken into consideration in computer-aided material design. For the material design, the specifications agreed with the customer are systematically analyzed to determine the essential decision criteria for the design of the material. Weak points and strengths of possibly existing material solutions for the specific application purpose are examined.
Once the requirements have been clarified, some basic questions concerning material selection will be answered, e.g.:
- Are there commercially available materials, which would be suitable with small modifications?
- Which material will yield the optimum technical and economical solution?
- Could the requirements possibly be fulfilled best using composite materials (see Raether, F.: Ceramic Matrix Composites – an Alternative for Challenging Construction Tasks)?
For the material selection, Fraunhofer-Center HTL uses Material databases and material indexes (see Raether, F.: Ceramics Facing Competition with other Materials) as well as thermodynamic analyses (see Arefin, M.L.; Raether, F.; Dolejš, D.; Klimera, A.: Phase formation during liquid phase sintering of ZnO ceramics).
For multiphase or porous materials, a specific Microstructure design (see Müller, Th.; Raether, F.: 3D modelling of ceramic composites and simulation of their electrical, thermal and elastic properties) is used. For this purpose, Fraunhofer-Center HTL has specially developed in-house software for the generation of realistic microstructures on the one hand, on the other hand commercially available finite element programs for the prediction of macroscopic material properties at its deposal. In order to have sufficiently precise microstructure properties simulation results, they are experimentally calibrated and validated. All necessary testing methods for the quantitative microstructural analysis and for measuring thermal, mechanical and electrical material properties are available. Structures are optimized by the computer for the specific tasks of the customer. Pores and melt phases are adequately considered. In the case of fiber-reinforced materials (CMC), realistic fiber distributions can be simulated. If required, Fraunhofer-Center HTL can develop the appropriate manufacturing processes for setting the optimal microstructure and material properties. The process development is carried out efficiently with the help of In-situ measurement methods and computer simulation.