Effects of cooling rate on solidification process in Al-Mg-Si alloy

Fei, W. D.; Kang, Suk‐Bong

doi:10.1007/bf00271010

Cited by 26 publications

(12 citation statements)

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“…These authors also reported that the relative fraction of b-AlFeSi phase increased as the cooling rate decreased, i.e., similarly to the tendency exhibited by the results of the present study, shown in Figure 15(a). In contrast, the Mg 2 Si IMC is a constituent of both binary and ternary eutectic mixtures, and as reported by Fei et al, [42] the ternary eutectic fraction increases with the increase in cooling rate attaining a maximum value at about 7. higher fraction of AlFe-type IMC obtained for the Al-3.0 wt pctMg-1.0 wt pctSi alloy. Figure 15(b) compares the hardness experimental values as a function of k 2 .…”

Section: Resultsmentioning

confidence: 63%

Characterization of Dendritic Microstructure, Intermetallic Phases, and Hardness of Directionally Solidified Al-Mg and Al-Mg-Si Alloys

Brito

Costa

Vida

et al. 2015

Metall Mater Trans A

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Despite the widespread application of Al-Mg-Si alloys, especially in the automotive industry, interrelations of solidification thermal parameters (cooling rate and growth rate), microstructure, and hardness are not properly established. For instance, the control of the scale of the microstructure on both Al-Mg and Al-Mg-Si alloys by adequate pre-programming of the solidification thermal parameters remains a task to be accomplished. In the present study, the directional solidification (DS) of these alloys under unsteady-state solidification conditions is investigated in an attempt to characterize the evolution of microstructural features, macrosegregation, and hardness as a function of local solidification thermal parameters along the DS castings length. Silicon addition to the Al-Mg alloy was found not to affect the sizes of primary and secondary dendrite arm spacings, but induced the onset of tertiary dendritic branches and affected also the size and distribution of intermetallic particles within the interdendritic regions. The Al-Mg-Si alloy is characterized by a more complex arrangement of phases, including binary (a-Al + Mg 2 Si) and refined ternary (a-Al + Mg 2 Si + AlFe(Si) eutectic mixtures. As a consequence, a higher Vickers hardness profile is shown to be associated with the ternary Al-Mg-Si alloy DS casting. For both alloys examined, hardness is shown to increase with the increase in the microstructural spacing according to Hall-Petch type equations.

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Section: Resultsmentioning

confidence: 63%

Characterization of Dendritic Microstructure, Intermetallic Phases, and Hardness of Directionally Solidified Al-Mg and Al-Mg-Si Alloys

Brito

Costa

Vida

et al. 2015

Metall Mater Trans A

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“…[1][2][3][4][5][6] These alloys have the properties of medium to high strength, excellent formability, and good corrosion resistance. Recent research has focused on the 6xxx series aluminum alloys.…”

Section: Introductionmentioning

confidence: 99%

Deformation and fracture behavior of two Al-Mg-Si alloys

Zhen

Kang

1997

Metall Mater Trans A

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Deformation and fracture behavior of two Al-Mg-Si alloys in different aging conditions has been studied by tensile testing, transmission electron microscope (TEM), and scanning electron microscope (SEM) observation. Tensile test results show that the strain hardening exponents (n values) of the two alloys decrease sharply at the early stage of artificial aging and are only 0.045 and 0.06, respectively, in the overaged condition. The sharp decrease of work hardening rate is believed to be one major reason that results in the rapid decrease of elongation to failure at the early stage of artificial aging. In fully aged conditions, dislocations are concentrated in narrow bands during plastic deformation of these alloys, which is responsible for the very low n values of the Al-Mg-Si alloys in peak aged and overaged conditions. The Si particles formed in the interior of grains of the higher Si containing alloy reduce the inhomogeneous deformation behavior. The TEM results show that large precipitates and precipitate-free zones (PFZs) along grain boundaries are formed in peak aged and overaged conditions, and SEM observations demonstrate that the tensile fracture modes of the two alloys in these aging conditions are completely intergranular with many small cusps decorated on facets of the fractured grain boundaries. Thus, the fracture process of both alloys is suggested to be that in which the high local stresses, built up where the slip band impinges on the grain boundaries, nucleate voids at the grain boundary precipitates by decohesion of the particle/PFZ interface, and then coalescence of these voids within the PFZ leads to the final fracture of these alloys.

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“…The Nital's reagent (98ml of ethanol and 2ml of HNO 3 ) and etching times of 2 min and 5s were used to reveal the macrostructures and the microstructures, respectively. The CET, if any, was measured along a vertical central section and from the bottom of the casting.…”

Section: Methodsmentioning

confidence: 99%

“…This is probably because dendrites are not readily discernible in the structure. On the other hand, a lot of research have been done on the relationships between dendritic growth and the solidification thermal parameters (G, V and Ṫ) for light alloys [2][3][4][5] .…”

Section: Introductionmentioning

confidence: 99%

Transient Directional Solidification of Cast Iron: Microstructure Formation, Columnar to Equiaxed Transition and Hardness

Spinola

Spinelli

2016

Mat. Res.

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A number of applications may require cast iron. Engine cylinder blocks, flywheels, gearbox cases, machine-tool bases may be manufactured by using grey cast iron while bearing surfaces with white cast iron. Thus, understanding the solidification behaviour of eutectic cast iron becomes an essential task, with certain points to be accomplished. Transient directional solidification may provide particular advantages in order to deal with these items, such as the large variation of growth rate (V) and cooling rate (Ṫ) values, which may allow a variety of microstructures and morphologies to be studied. The aim of this work is to examine the macrostructure regions, scale of the dendritic microstructure, proportions of the formed phases and hardness of samples obtained by transient directional solidification of a eutectic cast iron (Fe-3.5wt%C-2.5wt%Si). It was shown that a CET criterion should be based on a critical V value at the solidification front of about 0.6 mm/s. The effects of the formed phases, their proportions and λ 2 on hardness of the cast alloy are assessed.

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Effects of cooling rate on solidification process in Al-Mg-Si alloy

Cited by 26 publications

References 1 publication

Characterization of Dendritic Microstructure, Intermetallic Phases, and Hardness of Directionally Solidified Al-Mg and Al-Mg-Si Alloys

Characterization of Dendritic Microstructure, Intermetallic Phases, and Hardness of Directionally Solidified Al-Mg and Al-Mg-Si Alloys

Deformation and fracture behavior of two Al-Mg-Si alloys

Transient Directional Solidification of Cast Iron: Microstructure Formation, Columnar to Equiaxed Transition and Hardness

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