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The modification of cast AL-Mg2Si in SITU MMC by lithium

Hadian, R ; Sharif University of Technology | 2009

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  1. Type of Document: Article
  2. Publisher: 2009
  3. Abstract:
  4. Abstract The effects of both Lithium modification and cooling rate on the microstructure and tensile properties of an in-situ prepared Al-15% Mg2Si composite were investigated. Adding 0.3%Li reduced the average size of Mg2Si primary particles from ~30 μm to ~ 6 μm. The effect of cooling rate was investigated by the use of a mold with different section thickness from 3 to 9 mm. The results show a refinement of primary particle size as a result of both Li additions and increased cooling rate, and their effects were additive. Similarly, both effects increased UTS and elongation values. The refinement by Li and enhanced cooling rate is discussed in terms of an analogy with the effect of Sr and cooling rate in Al-Si alloys, and is similarly attributed to the effect of the alkali and alkaline earth metals deactivating oxide double films (bifilms) suspended in Al melts as favoured substrates for intermetallics
  5. Keywords:
  6. Oxides ; Al-Si alloy ; Al/Mg2Si composite ; Average size ; Bifilms ; Cooling rates ; Enhanced cooling ; In-situ ; Li additions ; MMC ; Modification ; Primary particle size ; Primary particles ; Section thickness ; Alkaline earth metals ; Aluminum ; Intermetallics ; Lithium ; Metallic matrix composites ; Oxide films ; Cooling
  7. Source: TMS 2009 Annual Meeting and Exhibition, San Francisco, CA, 16 February 2009 through 19 February 2009 ; 2009 , Pages 165-172 ; 9780873397353 (ISBN)