Morphological studies on β-FeSiAl5 phase in Al-7-Si-0.3Mg alloy with trace additions of Be, Mn, Cr, and Co
| Autor: | K. S. Raman, S. Murali, K. S. S. Murthy |
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| Rok vydání: | 1994 |
| Předmět: |
Alkaline earth metal
Materials science Mechanical Engineering Alloy Metallurgy Analytical chemistry Intermetallic chemistry.chemical_element Cleavage (crystal) Manganese engineering.material Condensed Matter Physics Microstructure Chromium chemistry Mechanics of Materials Phase (matter) engineering General Materials Science |
| Zdroj: | Materials Characterization. 33:99-112 |
| ISSN: | 1044-5803 |
| DOI: | 10.1016/1044-5803(94)90072-8 |
| Popis: | Although the detrimental effect of iron on the mechanical properties of A1-7Si-0.3Mg alloy has been well established, studies on neutralizing this effect have been very few and in- conclusive. The $\beta$-phase $(FeSiAl_5)$, seen in the interdendritic areas in the form of needles/plates, is responsible for this effect. In the present study, it has been observed that trace additions of Be, Cr, Mn, and Co, individually or combined, will tie up Fe to form new phases with altered morphologies such as Chinese scripts, polygons, stars, and irregular shapes. Cr-Fe and Mn-Fe phases are seen both in interdendritic regions and inside the a-A1 dendrites, while Co-Fe phase is mostly seen inside the a-A1 dendrites. However, Be-Fe phase is observed only inside the ~-A1 dendrites. Empirical formulas have been de- veloped from wavelength dispersive analysis on these relatively new Fe phases with trace additions. At higher Fe levels (0.8-1%) and with Be trace addition, individually or combined with Mn and Cr, fractographs reveal pyramids surrounded by cells, while other trace additions such as Mn, Cr, and Co reveal brittle cleavage fracture. All Be-added alloys, individually and combined with Mn and Cr additions, appear to neutralize the detrimental effect of Fe content on mechanical properties. |
| Databáze: | OpenAIRE |
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