Phase transformations in ZnAlCu alloys

Kovacheva, R.; Dobrev, Russi; Zadgorski, S.; Lilova, Albena

doi:10.1016/1044-5803(93)90065-4

Cited by 4 publications

(6 citation statements)

References 1 publication

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“…The observation contrasts with the previous work by Murphy, [4] who showed the ε phase is a stable phase above 268 ЊC. However, the finding of this research is in agreement with that of Kovacheva et al [8] B. Natural Aging…”

Section: A Solution Treatmentcontrasting

confidence: 80%

“…This anomaly can be understood by the following rationalization. As the solution-treatment temperature was increased from 250 ЊC to 310 ЊC, the copper content in the matrix was increased (due to the dissolution of ε phase [8] ); at the same time, the aluminum content in the matrix was decreased (due to the formation of T' phase). The effect associated with the increasing copper content on resistivity was balanced off by that associated with the decreasing aluminum content.…”

Section: A Solution Treatmentmentioning

confidence: 97%

“…[5] Some investigations [4,7] indicated that the ε phase was a stable phase at the B temperature above 268 ЊC and would be replaced by a stable phase T ' during long-time aging below 268 ЊC. In contrast, Kovacheva et al [8] found that the ε phase dissolved in phase above 260 ЊC through the measurement of differential thermal electromotive force in Zn-Al-Cu alloy. The crystal structure of T' phase (58 pct Al, 30 pct Cu, 12 pct Zn) present in the high-aluminum and high-copper zinc alloys was investigated by Arndt and Moeller [9] and Murphy.…”

Section: Introductionmentioning

confidence: 93%

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Phase transformation of Zn-4Al-3Cu alloy during heat treatment

Chao

1999

Metall Mater Trans A

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The phase transformation in Zn-4 Al-3 Cu alloy employing various solution-treatment temperatures (230 ЊC to 325 ЊC) was studied by means of microhardness, scanning electron microscopy (SEM), electron probe microanalysis (EPMA), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The starting microstructure of the as-cast Zn-4Al-3Cu alloy consists of an ␣ phase (aluminum-rich, fcc structure) in the matrix (zinc-rich, h.c.p. structure) prior to solution-treatment. A platelike ε phase with 3-m length and 0.5-m thickness was found in the phase matrix after solution-treating the as-cast material at 240 ЊC for 1 hour. The ε phase was then dissolved gradually back into the matrix above that temperature. A four-phase transformation, ␣ ϩ ε → T' ϩ , was observed from the temperature 250 ЊC to 310 ЊC, wherein the T' phase formed at the interface of ε platelet and phase matrix. This T' phase was further identified as a rhombohedral structure. As the solution-treatment temperature was increased to above 310 ЊC, the ε phase was completely dissolved back into the matrix and numerous ␤ phase particles were distributed uniformly in the matrix. The ␤ phase subsequently decomposed at room temperature to a fine ␣ phase embedded in the matrix. For the materials solution-treated above 250 ЊC, the microhardness of the matrix increased in 40 minutes during natural aging, which was associated with the formation of fine ε phase of 0.15-m diameter. The orientation relationship between this fine ε phase and phase was determined as [ 011] // [ 011] ε , (01 2) // (01 2) ε . 1 1 1 1

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Section: A Solution Treatmentcontrasting

confidence: 80%

Section: A Solution Treatmentmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 93%

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Phase transformation of Zn-4Al-3Cu alloy during heat treatment

Chao

1999

Metall Mater Trans A

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“…The network parameters estimated by X-ray diffraction were similar to those reported in previous studies [1,3,15] The phase is defined as Zn 4 Cu [1,15,16] or Zn 5 Cu [15,17]. The results of measurements of the chemical composition of the primary phase obtained by quenching for different alloys established a quantitative relationship between elements of the compound in the range of the proportions of atoms in molecules of 4:1 and 5:1 cited.…”

Section: Microstructural Analysismentioning

confidence: 97%

The effects of Cu and cooling rate on the fraction and distribution of epsilon phase in Zn–4Al–(3–5.6)Cu alloys

Jareño

Maldonado

Hernández

2010

Journal of Alloys and Compounds

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“…13). The sharp endothermic peak at about 280 • C signifies the eutectoid reaction [18]. During aging, Cu diffuses out of Al 4 Cu 9 resulting in the formation of AlCu and subsequent decrease in amount and disappearance of Al 4 Cu 9 phase, as observed in Fig.…”

Section: Alloy Za1mentioning

confidence: 89%