Quantification of precipitate fraction in Al–Si–Cu alloys

Guo, Ziqi; Sha, Wei

doi:10.1016/j.msea.2004.09.020

Cited by 24 publications

(8 citation statements)

References 10 publications

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“…The data used for the calculation of thermal conductivity is indicated in Figure 10(a) with crosses. The results from this investigation are in accordance with data presented in a review [14] for an A319 alloy similar to Stenal Rheo1. The data for the specific heat was used for the calculation of thermal conductivity for the T5 and T6 treated samples as well.…”

Section: Specific Heat and Thermal Expansionsupporting

confidence: 91%

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Influence of microstructure and heat treatment on thermal conductivity of rheocast and liquid die cast Al-6Si-2Cu-Zn alloy

Payandeh

Sjölander

Jarfors

et al. 2016

International Journal of Cast Metals Research

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This paper has been peer-reviewed but does not include the final publisher proof-corrections or journal pagination. Citation for the original published paper (version of record):Payandeh, M., Sjölander, E., Jarfors, A., Wessén, M. (2016) Influence of microstructure and heat treatment on thermal conductivity of rheocast and liquid die cast Al-6Si-2Cu-Zn alloy. International Journal of Cast Metals AbstractThermal conductivity of a rheocast telecom component made from Stenal Rheo1 (Al-6Si-2Cu-Zn) alloy was investigated in as-cast, T5 and T6 conditions. Conventionally liquid die cast samples were used as reference material. In the as-rheocast condition, a thermal conductivity of 153 W/mK at room temperature was measured. A T5 treatment at 250 or 300°C increased thermal conductivity to 174 W/mK. A T6 treatment resulted in further increase in thermal conductivity to 182 W/mK. The liquid die cast material exhibited lower thermal conductivity and higher hardness for all conditions compared to the as-rheocast material.The microstructural investigation revealed that the rheocast material consisted of coarse α1-Al particles formed during slurry preparation and fine α2-Al particles formed during solidification in the die cavity. Macrosegregation was observed as different the ratio of α1-Al particles to α2-Al particles in different locations in the rheocast component. The relation between microstructural characteristics and thermal diffusivity was investigated by determination of local thermal conductivity in the rheocast component and ratio of α1-Al particles to α2-Al particles. The results revealed that regions of rheocast component with a high amount of α1-Al particles showed higher thermal conductivity. WDS measurement showed that α1-Al particles contains lower concentrations of both Si and Cu inside compare to α2-Al particles. The reduced amount of solutes in the α1-Al particles was therefore determined as the root cause to higher thermal conductivity.Silicon precipitation was confirmed using calorimetry and dilatometry to take place between 200 and 250°C. A linear relation between the fraction of Si precipitates formed and the increase in thermal diffusivity was obtained. Silicon in solid solution is shown to have a strong influence (negative) on thermal conductivity. As silicon was precipitated during the heat treatment, thermal conductivity increased. For an optimal combination of thermal and mechanical properties it is therefore important to use an ageing temperature above the temperature for Si precipitation.

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Section: Specific Heat and Thermal Expansionsupporting

confidence: 91%

“…The heating rate was set to 10 K/min. The specific heat obtained was compared with data from a review by Mills et al [14] of thermos-physical properties. Density at room temperature was determined using Archimede's principle to be 2.70 ± 0.02 g/cm…”

Section: ( ) ( ) ( ) ( )mentioning

confidence: 99%

Influence of microstructure and heat treatment on thermal conductivity of rheocast and liquid die cast Al-6Si-2Cu-Zn alloy

Payandeh

Sjölander

Jarfors

et al. 2016

International Journal of Cast Metals Research

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“…JMatPro TM (acronym for "Java-based Materials Properties") is a Calphad-type software package for calculating and simulating the physical and thermophysical properties and behavior of multicomponent metallic systems. 34) This software has been extensively used with proven accuracy to simulate precipitation, 35) phase transformations and CCT diagrams, 36,37) solidification properties and high temperature strength, 38,39) among other physical phenomena and properties. To make the calculations in this paper, the program was coupled with Fe-DATA thermodynamic database.…”

Section: Methodsmentioning

confidence: 99%

Design of Composition in (Al/Si)-alloyed TRIP Steels

Gómez

García

Haezebrouck³

et al. 2009

ISIJ Int.

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Fig. 11. Comparison of the effect of the addition of (0.5-2 %) Mn, (0-1.5 %) Al, (0-1.5 %) Si to the steel presented in Table 2 on austenite volume fraction, austenite carbon content, carbon equivalent calculated with Eq. (1) and ideal diameter (DI) at 800°C; (a) effect of Mn-Al combinations with 0 % Si, (b) effect of Mn-Si combinations with 0 % Al, (c) effect of Si-Al combinations with 1.5 % Mn.

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“…2). The obtained degree of hardening depends on the volume fraction, the structure of the precipitates and the nature of the interface between the metastable phases and the aluminum matrix [14][15][16][17][18][19].…”

Section: Hardening Evolutionmentioning

confidence: 99%

INFLUENCE OF TRACES ADDITION OF TIN ON THE GROWTH AND ON THE COARSENING OF THE GUINIER-PRESTON ZONES IN Al-10% at.Ag ALLOY

Lourdjane

Hanifi

Raho

2017

Acta Metall Slovaca

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The formation of the Guinier-Preston zones in aluminium alloys is closely linked with the excess vacancies. Traces of tin added to an Al-Ag alloy exert an influence on the Guinier-Preston zones precipitation. Due to their high binding energy with vacancies, tin atoms trap some of these available to promote the diffusion of silver atoms for the formation of the Guinier-Preston zones. At 125°C, tin microalloying slows down the reaction of the Guinier-Preston zones precipitation. The diffusion coefficient of the solute atoms in the Sn free alloy and in the Sn added alloy are determined during the coarsening regime which obeys to the Lifshitz, Slyosov and Wagner theory.Keywords: Guinier-Preston zones; precipitation; coarsening; diffusion; vacancies; hardening 1 Introduction Al-Ag supersaturated solid solution evolves towards the equilibrium state following the sequence [1-4]: Supersaturated solid solution → Guinier-Preston (GP) zones → metastable γ' phase → equilibrium γ phase. The Guinier-Preston zones (GP), consisting of silver atom clusters, are coherent with the matrix. The metastable phase γ'(Ag2Al) is semi-coherent with the matrix and the equilibrium phase γ(Ag2Al), is incoherent with the matrix. Precipitation starts from the formation of GP zones, which are isomorphous with the matrix and, therefore, have a lower interfacial energy than intermediate or equilibrium precipitate phases that possess a distinct crystal structure. As a result, the nucleation barrier for GP zones is significantly smaller. The effect of microalloying elements on the behaviour of age-hardenable alloys such as Al-Ag is an interesting physical problem addressing the mechanisms of transport and aggregation of the solute. Trace elements have been found to exert a disproportionate influence on the structure and properties of Al alloys compared with the amounts added which may be less than 0,1 molar fraction . Most trace element effects arise because they modify the nucleation and the growth characteristics of the phases which form during precipitation [5][6][7][8][9]. It is well known that the formation of the GP zones in aluminium alloys is closely linked with the excess vacancies. A number of models of GP zones precipitation assisted by vacancies has been developed by several authors [10][11][12]. GP zones formation is governed by a transport mechanism of solute atoms by solute atom-vacancy complexes. The high binding energy between tin atoms and vacancies leads to the formation of vacancy-tin atom pairs and silver atom-vacancy-tin atom complexes.

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Quantification of precipitate fraction in Al–Si–Cu alloys

Cited by 24 publications

References 10 publications

Influence of microstructure and heat treatment on thermal conductivity of rheocast and liquid die cast Al-6Si-2Cu-Zn alloy

Influence of microstructure and heat treatment on thermal conductivity of rheocast and liquid die cast Al-6Si-2Cu-Zn alloy

Design of Composition in (Al/Si)-alloyed TRIP Steels

INFLUENCE OF TRACES ADDITION OF TIN ON THE GROWTH AND ON THE COARSENING OF THE GUINIER-PRESTON ZONES IN Al-10% at.Ag ALLOY

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