2. Material and methods
2.1. Material
For the experiments the standard die casting alloy 226 D (AlSi9Cu3(Fe), TSolidus 521 TLiquidus 593 °C) was used. The selected casting alloy is characterized by an excellent castability with average mechanical properties [1]. The hybrid support structure is produced from aluminum Al99.5 (1050) sheets and exhibits a countersank deepening for the positioning of the piezoelectric patches. Using Al99.5 implicates several advantages as reduced differences in thermal expansion coefficients, minimized corrosion problems and the opportunity of product recycling. To ensure the position of the module on the support structure during the casting cycle, the components are connected via adhesive bonding using a 2K-Epoxy resin (brand name: Loctite M-121HP Hysol®). Two piezoelectric patch designs have been chosen for the integration into aluminum castings, see figure 2. A commercially available patch transducer (brand name: DuraAct, distributor: PI Ceramic GmbH) as well as multilayered LTCC-PZT modules [7] can be applied in the described processing route. Both operate in the lateral extension mode (d31-mode). In the present paper LTCC-PZT modules without contacting wires are used as this sufficiently serves the purpose of approving the introduced concept.