The microstructural control of cast and mechanical properties of zinc-aluminium alloys

Savas, Mahmut A.; Altıntaş, Sabri

doi:10.1007/bf00595744

Cited by 37 publications

(21 citation statements)

References 3 publications

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“…Consequently, to control the properties of cast shape, and to reduction in load-bearing area. [1][2][3] alloys, it is necessary to understand the mechanism and It is generally found that the strength of a metallic material characterization of primary and secondary dendrite spacings increases as the grain size decreases. The well-known Hall-during the solidification of alloys.…”

Section: Introductionmentioning

confidence: 99%

Correlation between unsteady-state solidification conditions, dendrite spacings, and mechanical properties of Al-Cu alloys

Quaresma

Santos

Garcia

2000

Metall Mater Trans A

194

105

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The wide range of operational conditions existing in foundry and casting processes generates as a direct consequence a diversity of solidification microstructures. Structural parameters such as grain size and interdendritic spacings are strongly influenced by the thermal behavior of the metal/mold system during solidification, imposing, as a consequence, a close correlation between this system and the resulting microstructure. Mechanical properties depend on the microstructural arrangement defined during solidification. Expressions correlating the mechanical behavior with microstructure parameters should be useful for future planning of solidification conditions in terms of a determined level of mechanical strength, which is intended to be attained. In the present work, analytical expressions have been developed describing thermal gradients and tip growth rate during one-dimensional unsteadystate solidification of alloys. Experimental results concerning the solidification of Al-4.5 wt pct Cu and Al-15 wt pct Cu alloys and dendritic growth models have permitted the establishment of general expressions correlating microstructure dendrite spacings with solidification processing variables. The correlation of these expressions with experimental equations relating mechanical properties and dendrite spacings provides an insight into the preprogramming of solidification in terms of casting mechanical properties.

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Section: Introductionmentioning

confidence: 99%

Correlation between unsteady-state solidification conditions, dendrite spacings, and mechanical properties of Al-Cu alloys

Quaresma

Santos

Garcia

2000

Metall Mater Trans A

194

105

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“…In order to improve our understanding of the damping behavior and operative mechanisms in the MMCs with macroscopic pores and give some information on applications, the present investigation reports on a study of the damping behavior and relative dynamic modulus of foamed Zn-Al eutectoid alloy prepared using an air pressure infiltration process. Among high damping materials, Zn-Al alloys are considered to be the most excellent non-ferromagnetic damping alloys due to their attractive properties such as low melting point, low density, good ambient temperature mechanical properties, wear resistance and high damping capacity in a broad frequency range [6,7]. Damping measurements are, therefore, carried out over a wide range of temperatures, frequencies, and strain amplitudes.…”

Section: Introductionmentioning

confidence: 99%

Damping Behavior and Mechanism of Foamed Zn-Al Eutectoid Alloy

Wei

Han

2002

phys. stat. sol. (a)

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Subject classification: 62.40.+iThe present work investigates the damping behavior and mechanisms in foamed Zn-Al eutectoid alloy prepared by air pressure infiltration process. Pores in the foamed Zn-Al eutectoid alloy have macroscopic size of the order of a millimeter (0.5-1.0 mm) and in large proportions, typically up to 65 vol%. The damping behavior of the foamed Zn-Al eutectoid alloy is characterized by internal friction (IF). IF and relative dynamic modulus measurements at maximum surface shear strain of 20 Â 10 --6 have been made using a multifunction internal friction apparatus (MFIFA) at three discrete frequencies of 0.5, 1.0, and 3.0 Hz over a temperature range from room temperature to 400 C, while continuously changing temperature. Two IF peaks were found in the IF-temperature curves. The first is a grain boundary IF peak, which is associated with the diffusive flux on a crystalline boundary of Al. Its activation energy has been calculated to be (1.12 AE 0.04) eV and the pre-exponential factor t 0 is 10 --14 s in IF measurements. The second is a phase transition peak, which results from the transformation of Zn-Al eutectoid. Experimental results show that this phase transition IF peak is a function of _ T T=f ( _ T T rate of temperature change, f vibration frequency), but is not proportional to _ T T=f . Finally, the damping capacity of the foamed Zn-Al eutectoid alloy, with different macroscopic pore volume fractions and two different macroscopic pore sizes, were compared with that of bulk Zn-Al eutectoid alloy specimens. The damping capacity of the materials is shown to increase with increasing volume fraction of macroscopic pores and increase with decreasing macroscopic pore size. The operative possible damping mechanisms in the foamed Zn-Al eutectoid alloy were discussed in light of IF measurements.

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“…Microporosities are also shown in the microstructure as small and very dark spots in the interdendritic regions. [27] The microstructure after one-pass ECAE is shown in It is clear from the micrographs (Figures 3 through 5) that ECAE processing significantly changes the as-cast microstructure. After one pass, dendritic microstructure is distorted with grain refinement, and the phases are aligned with the inclination plane.…”

Section: Resultsmentioning

confidence: 97%

Microstructural Evolution and Mechanical Response of Equal-Channel Angular Extrusion-Processed Al-40Zn-2Cu Alloy

Pürçek

Saray

Караман

et al. 2009

Metall Mater Trans A

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Microstructural evolution, tensile properties, and impact toughness of an aluminum-zinccopper (Al-40Zn-2Cu) alloy subjected to repetitive equal-channel angular extrusion (ECAE) up to four passes following either route A or route B C were investigated. The experimental results reveal that the ECAE eliminated as-cast dendritic microstructure along with casting defects such as microporosities almost completely. The ECAE-processed samples consisted of mostly elongated microconstituents via route A and equiaxed microconstituents via route B C . The high stresses imposed in ECAE lead to the fragmentation of the copper-rich h phase into smaller particles with significant fragmentation occurring in the first pass and additional breaking in the subsequent passes in both routes. The ECAE processing simultaneously increased both the strength and ductility of the alloy as compared to the as-cast state, regardless of the processing route and number of passes. The deformation behavior of as-cast Al-40Zn-2Cu alloy has changed from brittle to ductile mode after ECAE due to the microstructural refinement, deformation-induced homogenization, and reduction of porosities. The limited impact toughness of as-cast alloy was significantly improved by multipass ECAE, especially in route A.

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The microstructural control of cast and mechanical properties of zinc-aluminium alloys

Cited by 37 publications

References 3 publications

Correlation between unsteady-state solidification conditions, dendrite spacings, and mechanical properties of Al-Cu alloys

Correlation between unsteady-state solidification conditions, dendrite spacings, and mechanical properties of Al-Cu alloys

Damping Behavior and Mechanism of Foamed Zn-Al Eutectoid Alloy

Microstructural Evolution and Mechanical Response of Equal-Channel Angular Extrusion-Processed Al-40Zn-2Cu Alloy

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