|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||Cast Shop Technology: An LMD Symposium in Honor of Wolfgang Schneider
||Mechanism of Zirconium Poisoning Effect on TiB2 Inoculation in Aluminium Alloys
||Yun Wang, Li Zhou, Zhongyun Fan
|On-Site Speaker (Planned)
Although TiB2 particles have been used as the heterogeneous nuclei for more than six decades, the mechanism of heterogeneous nucleation is not fully understood. For instance, the efficiency of TiB2 inoculation to achieve grain refinement was decreased significantly by the addition of a small amount of Zr (e.g., 500ppm), resulting in a fully columnar and coarse grain structure. In the present work, the mechanism of the so-called “poisoning” effect has been investigated by advanced analytical microscopy, including aberration-corrected high resolution STEM at atomic scale. Adsorption of Zr atoms was observed at the Al/TiB2 interface. More significantly, the adsorbed Zr atoms in the atomic mono-layer were ordered in 2-dimension since it can be seen from the STEM Z-contrast HAADF image that the brightness of the layer varies periodically when viewing in [10-10] direction of the TiB2. The effect of the Zr atom adsorption on heterogeneous nucleation was discussed.
||Planned: Light Metals Volume