The aim of the project is to determine the fundamentally effects of impurities and individual micro-alloying elements (eg. as vanadium V, titanium Ti, calcium Ca, zirconium Zr, potassium K, phosphorus P and others) or combinations of these trace elements in aluminum alloys and their impact on the quality of aluminum castings.
As a result, limit values and tolerances for individual impurities (trace elements) should be defined and determined. Further on practical study methods should be developed that support on the one hand a reliable series production of high-quality alloys and castings and on the other hand the procurement of aluminum alloys by the foundries.
The casting trials in industry-related standards were performed on the base of a high purity alloy AlSi7Mg0,3 with systematic addition (30ppm, 300ppm, 3000ppm) of micro-alloying elements, controlled by chemical analysis with an emission spectrometer.
Technological properties as flowability, hot crack susceptibility and shrinkage cavity formation were evaluated. Static and dynamic material testing, like tensile tests, hardness measurements and Woehler curves was implemented. The thermo-physical properties as specific heat capacity, thermal expansion, temperature conductivity, density and heat conductivity were measured.
Phase calculations by ThermoCalc-Software, to simulate the formation of intermetallic phases and their impact on the microstructure are compared to classical metallography and additional SEM/TEM-investigations.
SEM/EDXS/EBSD-measurements for the micro-characterization of the structure and the composition of the intermetallic phases are made on cross sections (figures 1-4).
Out from regions/phases of interest TEM-lamellas are prepared with the FIB-technique and transferred to TEM for using EDXS/EELS/EFTEM and diffraction methods for the nano-characterization of these phases.
The authors want to thank the Austrian Research Promotion Agency (FFG) for financial support (PN845411).
Figures:
Figure 1: Backscattered Electron (BSE) Image of AlSi7Mg0,3 doped with 300ppm zirconium - fine needles form this coralliform shaped Al3Zr-phase
Figure 2: Backscattered Electron (BSE) Image of AlSi7Mg0,3 doped with 3000ppm zirconium – diagonal crossed (St. Andrew´s cross shaped) Al3SiZr-phase
Figure 3: Backscattered Electron (BSE) Image of AlSi7Mg0,3 doped with 3000ppm zirconium and 3000pm calcium - fine needles form this coralliform shaped Al3Zr-phase - beneath the diagonal crossed (St. Andrew´s cross shaped) Al3SiZr-phase
Figure 4: Backscattered Electron (BSE) Image of AlSi7Mg0,3 doped with 30ppm zirconium and 30ppm vanadium - fine needles form this coralliform shaped Al3Zr-phase – beneath the blocky VB2 with the spiky Vx-Zry-phase
To cite this abstract:
Hartmuth Schroettner, Thomas Pabel, Tose Petkov, Sabrina Mertschnigg, Anita Rossmann-Perner; Effect of trace elements on the material properties of an aluminium casting alloy. The 16th European Microscopy Congress, Lyon, France. https://emc-proceedings.com/abstract/effect-of-trace-elements-on-the-material-properties-of-an-aluminium-casting-alloy/. Accessed: December 3, 2023« Back to The 16th European Microscopy Congress 2016
EMC Abstracts - https://emc-proceedings.com/abstract/effect-of-trace-elements-on-the-material-properties-of-an-aluminium-casting-alloy/