An analysis of cooling rate influence on the sequence of intermetallic phases precipitation in some commercial aluminium alloys

It is known that the formation of cavities during superplastic deformation can be correlated with the development of stress concentrations at irregularities along grain boundaries such as particles, ledges and triple points. In commercial aluminium alloys Al-Fe-Si particles or other coarse constituents may play an important role in cavity formation.Cavity formation during superplastic deformation was studied by optical metallography and transmission scanning electron microscopic investigations on Al-Mg-Si and Al-Mg-Mn alloys. The structure of particles was characterized by selected area diffraction and X-ray micro analysis. The volume fraction of “voids” was determined on mechanically polished surface.It was found by electron microscopy that strongly deformed regions are formed during superplastic forming at grain boundaries and around coarse particles.According to electron diffraction measurements these areas consist of small micro crystallized regions. See Fig.l.Comparing the volume fraction and morphology of cavities found by optical microscopy a good correlation was established between that of micro crystalline regions.

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Development of an Extraction Replica Technique for the Analysis of Intermetallic Phases in Aluminium Alloys / Entwicklung eines Ausziehabdruckverfahrens für die Analyse von intermetallischen Phasen in Aluminiumlegierungen

Practical Metallography ◽

10.1515/pm-1986-231003 ◽

1986 ◽

Vol 23 (10) ◽

pp. 485-492

Author(s):

Jan Strid ◽

Christian J. Simensen

Keyword(s):

Aluminium Alloys ◽

Intermetallic Phases ◽

Replica Technique ◽

Extraction Replica

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Structures and Properties of Commercial Aluminium Alloys after Severe Straining

Advanced Light Alloys and Composites ◽

10.1007/978-94-015-9068-6_55 ◽

1998 ◽

pp. 421-426

Author(s):

M. V. Markushev ◽

C. C. Bampton ◽

M. Yu. Murashkin ◽

D. A. Hardwick

Keyword(s):

Aluminium Alloys ◽

Structures And Properties ◽

Commercial Aluminium

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The Failure Degradation of Recycled Aluminium Alloys with High Content of β-Al5FeSi Intermetallic Phases

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.403.97 ◽

2020 ◽

Vol 403 ◽

pp. 97-102

Author(s):

Denisa Medvecká ◽

Lenka Kuchariková ◽

Milan Uhríčik

Keyword(s):

Aluminium Alloys ◽

Cast Alloy ◽

Intermetallic Phases ◽

X Ray ◽

Fracture Surfaces ◽

Phase Lead ◽

Micro Cracks ◽

Fe Content ◽

Increased Risk ◽

Cast Alloys

In this study, the effect of the β-Al5FeSi phases on fracture surfaces in secondary AlSi7Mg0.3 cast alloys with common and higher amount of iron was investigated. Iron addition caused the formation of different Fe-rich intermetallic phases in aluminium alloys. Components made of secondary aluminium alloys commonly have a higher amount of such phases. Sharp needles as β-Al5FeSi phase lead to initiate stress tension, thereby contributing to increased risk of micro-cracks formation on the fracture surfaces. To determine the effect of β-Al5FeSi to fracture surfaces of AlSi7Mg0.3 cast alloy, SEM microscopy with energy-dispersive X-ray spectroscopy (EDX) was used to study the amount of needles phases, their morphology and violation wave. It was found that increasing Fe content increased the size and the number of Al5FeSi phases. The fractographic analysis of fracture surfaces shows an increasing amount of cleavage fracture in materials with a higher amount of iron, too.

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