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Microstructural evolution of Al-20Si-5Fe alloy during rapid solidification and hot consolidation
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Microstructural evolution of Al-20Si-5Fe alloy during rapid solidification and hot consolidation

Rajabi, M

Microstructural evolution of Al-20Si-5Fe alloy during rapid solidification and hot consolidation

Rajabi, M ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1007/s12598-009-0122-3
  3. Abstract:
  4. Al-20Si-5Fe melt was rapidly solidified into particles and ribbons and then consolidated to near full density by hot pressing at 400°C/250 MPa/1 h. According to the eutectic-growth and dendritic-growth velocity models, the solidification front velocity and the amount of undercooling were estimated for the particles with different sizes. Values of 0.43-1.2 cm/s and 15-28 K were obtained. The secondary dendrite arm spacing revealed a cooling rate of 6 × 105 K/s for the particles with an average size of 20 μm. Solidification models for the ribbons yielded a cooling rate of 5 × 107 K/s. As a result of the higher cooling rate, the melt-spun ribbons exhibited considerable microstructural refinement and modification. The size of the primary silicon decreased from approximately 1 μm to 30 nm while the formation of iron-containing intermetallic compounds was suppressed. Supersaturation of the aluminum matrix in an amount of ∼7 at.% Si was noticed from the XRD patterns. During the hot consolidation process, coarsening of the primary silicon particles and precipitation of β-Al5FeSi phase were observed. Evaluation of the compressive strength and hardness of the alloy indicated an improvement in mechanical properties due to the microstructural modification
  5. Keywords:
  6. Al-Si-Fe alloy ; Aluminum matrix ; Average size ; Consolidation process ; Cooling rate ; Cooling rates ; Different sizes ; Growth velocity ; Iron containing intermetallics ; Melt-spun ribbons ; Microstructural modification ; Microstructural refinement ; Primary silicon ; Rapidly solidified ; Secondary dendrite arm spacing ; Solidification fronts ; Solidification models ; XRD patterns ; Aluminum ; Compressive strength ; Cooling ; Crystallization ; Dendrimers ; Hardness ; Hot pressing ; Intermetallics ; Iron alloys ; Mechanical properties ; Melt spinning ; Microcrystalline silicon ; Microstructure ; Precipitation (chemical) ; Silicon ; Silicon alloys ; Silicon compounds ; Undercooling ; Rapid solidification
  7. Source: Rare Metals ; Volume 28, Issue 6 , 2009 , Pages 639-645 ; 10010521 (ISSN)
  8. URL: https://link.springer.com/article/10.1007/s12598-009-0122-3