Determination of the growth restriction factor and grain size for aluminum alloys by a quasi-binary equivalent method

Grain refinement of titanium alloys during solidification is believed to have many benefits for processing and properties. Recent work has emphasized the importance of solute elements in grain refining cast titanium and it was demonstrated that the growth restriction factor is useful for predicting the grain refining effectiveness of solute elements in titanium. Despite oxygen being the major impurity element present in titanium alloys and having been previously identified as a theoretical growth restricting solute, its effect as a β-grain refiner is still unexplored. This paper investigates the effect of oxygen on the grain size in cast titanium alloys.

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Prediction of As-Cast Grain Size of Inoculated Multicomponent Aluminum Alloys

Materials Science Forum ◽

10.4028/www.scientific.net/msf.790-791.185 ◽

2014 ◽

Vol 790-791 ◽

pp. 185-190 ◽

Cited By ~ 5

Author(s):

Qiang Du ◽

Yan Jun Li

Keyword(s):

Numerical Simulation ◽

Grain Size ◽

Aluminum Alloys ◽

Cooling Curve ◽

Restriction Factor ◽

Grain Sizes ◽

Cooling Conditions ◽

Proposed Model ◽

Simulation Results ◽

Melt Composition

In this paper, an extendedMaxwell-Hellawell numerical grain size prediction model is employed to predictas-cast grain size of inoculated aluminum alloys. Given melt composition,inoculation and cooling conditions, the model is able to predict maximumnucleation undercooling, cooling curve and final as-cast grain size of multi-componentalloys. The proposed model has been applied to various binary andmulticomponent alloys. Upon analyzing the numerical simulation results, it isfound that for both binary and multi-component alloys, grain size does not havea one-to-one relation with Growth Restriction Factor, Q, but has a clear ubiquitous correlation with the average diffusivity-weightedQ, defined as W in this paper. This founding helps solve the controversy seen inthe recent work on analytical grain size and Q relations. It also has been used to interpret the scatters seenin the measured grain sizes as a function of Q values reported in the literature.

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Effects of zinc, lithium, and indium on the grain size of magnesium

Journal of Materials Research ◽

10.1557/jmr.2009.0205 ◽

2009 ◽

Vol 24 (5) ◽

pp. 1722-1729 ◽

Cited By ~ 30

Author(s):

A. Becerra ◽

M. Pekguleryuz

Keyword(s):

Solid Solution ◽

Grain Size ◽

Binary System ◽

Electron Probe ◽

Binary Alloys ◽

Growth Restriction ◽

Restriction Factor ◽

Copper Mold ◽

Quaternary Alloys ◽

Zn Alloys

The grain size of magnesium solid-solution alloys with lithium, indium, and/or zinc has been determined. Lithium, indium, and zinc additions decreased the grain size, D, of magnesium solid-solution alloys cast in a copper mold. The most effective grain refinement was obtained by zinc. In binary Mg–Zn alloys, grain size is related to the growth restriction factor, Q as D = 94 + 312/Q. In Mg–Li and Mg–In binary alloys, grain size versus growth relationships described as D = a + b/Q indicated that these alloys have lower numbers of nucleants but with higher potency than the Mg–Zn binary system. For Mg–Li and especially Mg–In, grain size could be related to growth restriction as D = 383Q−n with higher R2. Ternary and quaternary alloys based on Mg–Zn with Li and/or In additions also follow the D = a + b/Q relationship with the parameters indicating a larger number of lower potency nucleants than the Mg–Zn binary alloys. Electron probe microanalysis showed that Mg–Zn alloys exhibit pronounced and persistent grain-boundary enrichment of Zn, pointing toward Scheil solidification.

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Evaluating the Growth Restriction Factor in Stable and Metastable Al-Si-Ti Alloy Solidification

Materials Science Forum ◽

10.4028/www.scientific.net/msf.690.7 ◽

2011 ◽

Vol 690 ◽

pp. 7-10

Author(s):

Artem Kozlov ◽

Rainer Schmid Fetzer

Keyword(s):

Intermetallic Phases ◽

Growth Restriction ◽

Restriction Factor ◽

Ti Alloy ◽

Alloy Solidification ◽

Multicomponent Alloys ◽

Growth Restriction Factor ◽

Ti Alloys ◽

Primary Intermetallic Phases

Evaluation concepts for theGrowth Restriction Factor, Q, in multicomponent alloys are discussed and illustrated for ternary Al-Si-Ti alloys involving precipitation of primary intermetallic phases.

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