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Two-Zone Microstructures in Al-18Si Alloy Powders.pdf
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- Author(s) / Creator(s)
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Hypereutectic Al-18wt.%Si alloy is widely used in automotive industry as a wear resistant alloy for engine components. However, in the last few years, this traditional composition is being considered for processing by different rapid solidification methods. Positive points include its low thermal expansion and uniform distribution of surface oxides. Nevertheless, microstructural aspects of Al-Si powders of 18 wt. % Si still need to be addressed, such as, the eutectic Si morphology, size and distribution generated by different process conditions during rapid solidification. Based on a detailed quantitative analysis of the microstructures of rapid solidified Al-18wt.%Si in this work, solidification conditions that yield specific Si morphologies, Si spacing and thermal cooling conditions are outlined. The focus is determining the solidification conditions that will yield a specified shape of eutectic Si. It is shown that Si morphology is dependent on a combination of growth velocity (based on modified J-H model) and temperature gradient. Furthermore, the highest hardness is achieved with globular morphologies of Si. The processing conditions required to achieve these properties are outlined.
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- Date created
- 2017-01-01
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- Type of Item
- Article (Published)