Study of the mechanism of grain refinement of aluminum after additions of Ti- and B-containing master alloys

Johnsson, Mats; Bäckerud, L.; Sigworth, Geoffrey K.

doi:10.1007/bf02657335

Cited by 154 publications

(93 citation statements)

References 11 publications

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“…This is because Ti has a relative Q value 40 to 100 times that of most alloying elements. 30) Likewise in high solute alloys such as alloy 2014, the value of Q 0 is approximately 22 and the addition of Ti has little effect on the grain size of alloys ( Fig. 2(b)).…”

Section: Experimental Observationsmentioning

confidence: 97%

Grain Morphology of As-Cast Wrought Aluminium Alloys

2011

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Two of the most important microstructural features of alloys are the grain size and the secondary dendrite arm spacing (SDAS) and these two factors are shown to combine together to describe the grain morphology. Both grain refinement and the SDAS depend upon alloy composition through constitutional undercooling, but in different ways. It is shown that there is a 'characteristic' SDAS for each alloy at a particular cooling rate, and reducing the grain size causes the grain morphology to change from dendritic to cellular/rosette-like to globular or spherical. Increasing the cooling rate refines both the SDAS and the grain size, but reduces the SDAS more rapidly leading to finer, more dendritic grain structures. Particular ratios of grain size to SDAS are used to define each morphology and it is shown how these can assist with obtaining a required grain size and morphology through the use of solidification conditions and alloy chemistry.

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Section: Experimental Observationsmentioning

confidence: 97%

Grain Morphology of As-Cast Wrought Aluminium Alloys

2011

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“…In order to understand the mechanisms underlying the grain refinement with different Mg concentration and intensive melt shearing, grain size data for both sheared and non-sheared TP-1 samples are plotted in Fig. 10 against the growth restriction factor Q. Parameters used to calculate growth restriction factor Q are adopted from references [10,48]. For the samples with intensive melt shearing, the grain size decreases only slightly with the increase of Q.…”

Section: Mechanisms Of Enhanced Heterogeneous Nucleationmentioning

confidence: 99%

Mechanisms of enhanced heterogeneous nucleation during solidification in binary Al–Mg alloys

Li¹,

Wang²,

Fan³

2012

Acta Materialia

177

120

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This paper investigates the mechanisms involved in the grain refinement of Al-Mg alloys through varying the Mg content and applying intensive melt shearing. It was found that the oxide formed in Al-Mg alloys under normal melting conditions is MgAl 2 O 4 , which displays an equiaxed and faceted morphology with {111} planes exposed as its natural surfaces. Depending on the Mg content, MgAl 2 O 4 particles exist either as oxide films in dilute Al-Mg alloys (Mg<1wt.%) or naturally dispersed discrete particles in more concentrated Al-Mg alloys (Mg>1wt.%). Such MgAl 2 O 4 particles can act as potent sites for nucleation of α-Al grains, which is evidenced by the well-defined cube-on-cube orientation relationship between MgAl 2 O 4 and α-Al. Enhanced heterogeneous nucleation in Al-Mg alloys can be attributed to the high potency of MgAl 2 O 4 particles with a lattice misfit of 1.4% and the increased number density of MgAl 2 O 4 particles due to either natural dispersion by the increased Mg content or forced dispersion through intensive melt shearing. It was also found that intensive melt shearing leads to significant grain refinement of dilute Al-Mg alloys by effective dispersion of the MgAl 2 O 4 particles entrapped in oxide films, but it has marginal effect on the grain refinement of concentrated Al-Mg alloys, where MgAl 2 O 4 particles have been naturally dispersed into individual particles by the increased Mg content.

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“…The TiAl3 intermetallic phase regions behave as cathode and the near α -Al phase behaves anodically and dissolves. By the Ti content 6 % the average area ratio of the intermetallic phases increases [12]. So with increasing aging time the size of the local cathode areas increases and this leads more dissolution of the Al matrix.…”

Section: Microstructure Characterizationbefore Corrosionmentioning

confidence: 99%

Corrosion Behaviorof Aluminum Alloy 6061withgrain RefinerAl- 6Tiin Salt Solution (3.5%NaCl) After Heat Treatment

Elsharkawy¹

2017

THE IJES

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Study of the mechanism of grain refinement of aluminum after additions of Ti- and B-containing master alloys

Cited by 154 publications

References 11 publications

Grain Morphology of As-Cast Wrought Aluminium Alloys

Grain Morphology of As-Cast Wrought Aluminium Alloys

Mechanisms of enhanced heterogeneous nucleation during solidification in binary Al–Mg alloys

Corrosion Behaviorof Aluminum Alloy 6061withgrain RefinerAl- 6Tiin Salt Solution (3.5%NaCl) After Heat Treatment

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