The Interface of TiB2 and Al3Ti in Molten Aluminum
| Autor: | Haibin Ma, Xiaoming Wang, Qingyou Han, Wei Vian, Jie Song |
|---|---|
| Rok vydání: | 2015 |
| Předmět: |
010302 applied physics
Materials science Metallurgy Alloy Metals and Alloys Nucleation chemistry.chemical_element 02 engineering and technology engineering.material 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Casting Grain size Crystal chemistry Mechanics of Materials 0103 physical sciences Materials Chemistry engineering 0210 nano-technology Layer (electronics) Dissolution Titanium |
| Zdroj: | Metallurgical and Materials Transactions B. 47:3285-3290 |
| ISSN: | 1543-1916 1073-5615 |
| DOI: | 10.1007/s11663-015-0570-0 |
| Popis: | In the grain refinement of aluminum, Al3Ti and TiB2 particles are introduced to reduce the casting grain size down to 200 micrometer level, which makes cold working possible. The particles are brought in by the addition of Al-Ti-B-type master alloys. It is generally believed that TiB2 particles are stable and nucleate α-Al grains in solidification in the presence of titanium in solution from the dissolution of Al3Ti particles in the master alloys. The titanium in solution either forms Al3Ti layers on the surface of TiB2 particles to promote the nucleation of α-Al grains or remains as solute to restrict the growth of α-Al grains in solidification. However, a consensus on a grain refinement mechanism is still to be reached due to the lack of direct observation of the three phases in castings. This paper presents finding of the TiB2/Al3Ti interfaces in an Al-Ti-B master alloy. It demonstrates a strong epitaxial growth of Al3Ti on the surface of TiB2 particles, a sign of the formation of an Al3Ti layer on the surface of TiB2 particles in grain refinement practice. The Al3Ti layer has a crystal coherency with α-Al and hence offers a substrate for heterogeneous nucleation of α-Al grains. However, the layer must be dynamic to avoid the formation of compounded Al3Ti and TiB2 particles leading to the loss of efficiency in grain refinement. |
| Databáze: | OpenAIRE |
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