Microstructure and mechanical properties of micro tensile specimens made of CuAl10Ni5Fe4 produced by micro casting

In this paper the results of micro tensile tests of specimens produced by vacuum pressure casting (VPC) and centrifugal casting (CC) with varied mould temperatures are described. The microstructure of VPC-micro specimens is clearly different from CC-micro specimens. Due to the large tolerance range of the chemical composition of the aluminum bronze CuAl10Ni5Fe4 and process instabilities the microstructure of batches of VPC-micro specimens can be very fine grained as well as very coarse grained even if the process parameters were nominally the same. As a consequence the mechanical properties of micro specimen show a wide range, e. g. the ultimate tensile strength (VPC, mould temperature T-m = 1,000 degrees C) is between 670 and 1,000 MPa. Within one batch (ca. 15 specimens) the scatter of microstructure and mechanical properties is clearly smaller. If the chemical composition of the material is nearly constant for a larger number of batches, then the production process of vacuum pressure casting leads reproducibly to nearly identical microstructure and mechanical properties.