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Decomposition of Fe-intermetallics in Sr-modified cast 6XXX type aluminum alloys for automotive skin

“…As these particles are mostly observed attached to the 600 ppm Sr-modified sample of Al-7 pct Si alloy (as part of a study currently underway [19] ), is shown here solely for sides or the end of the ␤-phase platelets, it could be assumed that the Si rejected from the latter reacts with the Sr in the the purpose of providing more information on the nature of these particles. Wavelength dispersion spectroscopic (WDS) formed due to the change in the intermetallic phase from ␤-Al 5 FeSi to ␣-Al 8 Fe 2 Si.…”

“…Al-7 pct Si-0.8 pct Fe alloy. [19] In the absence of Sr (Fig. A comparison of the two cases indicates that the ␣-15(a)), the ␤ phase appears in the form of entire, solid Al 15 (Fe,Mn) 3 Si 2 script phase is much more stable than the platelets, whereas, in the Sr-containing alloy (Fig. 15(b)), ␤-Al 5 FeSi phase, in that it does not begin to decompose these platelets are more perforated, than solid, in nature, due until a very high amount of Sr is added to the alloy.…”

The Effect of Modification and Grain Refining on the Microstructure and Mechanical Properties of A356 Alloy

“…With the grain refining treatment, it is possible to reduce final grain size and improve mechanical properties. Liu et al [4] report that pores forming around aluminum and strontium oxides when Al-Si alloy is modified with strontium and β-Al5FeSi intermetallics nucleate around pores. The relationship between strontium and formation of pores does not only depend on amount of strontium, but also on hydrogen content of liquid aluminum.…”

Modelling of different entrainment mechanisms and their influences on the mechanical reliability of Al-Si castings

“…The formation of entrainment defects occurs in two main ways: a) folding over of oxide films, and b) direct entrainment of gas bubbles.When liquid alloy is transferred or poured from, say, a crucible into the mould, the oxide layer formed on the free surface of the fluid by contact with the surrounding atmosphere will be easily broken or folded and then entrained into the bulk liquid by the surface turbulence ( Figure 1a). The poorly bonded oxide layers, with entrapped gas, lead to the formation of cracks in the solidified castings, and provide sites for the heterogeneous nucleation of microprosity [1,2]. Microbubbles can also be directly entrained into the liquid metal by flows such as plunging jets and hydraulic jumps (return waves) [3], as shown in Figure 1b.…”