Murali, S and Row, Guru TN and Sastry, DH and Raman, KS and Murthy, KSS (1994) Crystal structure of $\beta-FeSiAl_5$ and (Be-Fe)-$BeSiFe_2Al_8$ phases. In: Scripta Metallurgica et Materialia, 31 (3). pp. 267-271.
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Among the aluminium cast alloys, the precipitation hardenable AI-7Si-0.3Mg is perhaps the most widely used alloy. Iron is present as an impurity in this alloy, and an increase in iron content adversely affects the fracture toughness and other mechanical properties (1,2). Correlation with microstructure reveals that $\beta-FeSiAI_5$ intermetallic compound, mostly seen in interdendritic areas (1,2), is responsible for the poor tensile properties. Beryllium trace addition ties up iron, forming a new phase with altered morphology (Chinese scripts)seen only inside the $\alpha-AI$ dendrites (3). The formation of the Be-Fe phase inside ~-AI dendrites is speculated to be due to a peritectic reaction (4). Although analysis of the Be-Fe phase has been carried out in an earlier study (5), the crystal structure of this phase has not been reported. Generally, phases that act as nucleants ($TiAI_3$ in aluminium alloys) by peritectic reaction have a crystal structure similar to that of the matrix, or certain crystallographic planes of the nucleants are coherent with the matrix (6,7).
|Item Type:||Journal Article|
|Additional Information:||The copyright of this article belongs to Elsevier.|
|Department/Centre:||Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
|Date Deposited:||17 Oct 2006|
|Last Modified:||19 Sep 2010 04:31|
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