On the Serration in Al-Mg Alloys at Elevated Temperatures

Ikeno, Susumu; Watanabe, Tetuya; Tada, Shizuo

doi:10.2320/jinstmet1952.47.3_231

Cited by 19 publications

(7 citation statements)

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“…The specimen B after natural aging for 35 Ms, which shows the additional increase in the critical strain, contains no less 98% of solute Mg elements, indicating that the decrease in the solute Mg element accompanied with the increase in the critical strain is vanishingly small. The proposed mechanism that the decrease in the solute Mg elements causes the increase in the critical strain 5,13) is not consistent with these analyses. Thus, it is strongly suggested that the very existence of the Zn-Mg clusters is responsible for the increase in the critical strain.…”

Section: The Correlation Between Serrated Ow and Micro-mentioning

confidence: 35%

“…These results suggest that the formation of the Zn-Mg clusters affects the increase in the critical strain. The formation of these clusters, however, simultaneously brings about the decrease in the amount of solute Mg atoms, which is reported to in uence the critical strain 5,13) . Thus, the change in the critical strain may be in uenced not only by the formation of clusters but also by the decrease in the amount of solute Mg atoms in the matrix.…”

Section: The Correlation Between Serrated Ow and Micro-mentioning

confidence: 99%

“…The serrated ow is caused by dynamic strain aging (DSA), where the solute atoms diffuse in the matrix and interact with dislocations in motion during deformation 1,2) . Brief analyses have been done to reveal a great deal about the DSA phenomena with an emphasis on the effects of solute concentration and process factors such as strain, strain rate, deformation temperature and so on [3][4][5][6][7] . As for the microstructural factors, it has been reported that nano-ordered clusters (or G.P.…”

Section: Introductionmentioning

confidence: 99%

“…zones) and precipitates suppress the serrated ow 5,[8][9][10][11][12][13] . These mechanisms, which have been proposed as several theories 5,[8][9][10][11][12][13] , are not persuasive enough because of the limitations of the standard analysis such as transmission electron micrograph (TEM) to characterize the nano-ordered clusters or precipitates in detail. It is therefore desirable to clarify the role of them in more detail.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Precipitation State on Serrated Flow in Al-Mg(-Zn) Alloys

et al. 2016

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The effects of the aging conditions on the serrated ow in Al-Mg(-Zn) alloys were investigated, focusing on the precipitation states. Al6%Mg and Al-6%Mg-3%Zn alloys were naturally and arti cially aged after solution treated and quenched. The serrated ow was examined by tensile test. As for the Al-6%Mg-3%Zn alloy, the naturally aged specimens show the increase in the critical strain for serrated ow. The Zn-Mg clusters are formed during natural aging. Furthermore, the increase in the number density and the size of these clusters corresponds to the increases in the critical strain, which reveals that the formation of these coherent clusters is one of the dominant factors for delaying the onset of serrated ow. On the other hand, as for the arti cially aged specimens in the under-aged conditions, the transformation of the clusters to the incoherent meta-stable precipitates brings about the decrease in the critical strain. Furthermore, the increase in the volume fraction of these precipitates in the over-aged conditions reduce the stress amplitude of serrated ow, which are brought about by the decrease in the solute Mg content.

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Section: The Correlation Between Serrated Ow and Micro-mentioning

confidence: 35%

Section: The Correlation Between Serrated Ow and Micro-mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effects of Precipitation State on Serrated Flow in Al-Mg(-Zn) Alloys

et al. 2016

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“…When clusters and GP zones are formed by aging, the amount of Mg in the solid solution decreases, and accordingly, C 0 decreases. D also increases as temperature increases [25,26]. It is difficult to measure the diffusion rate of solute atoms at low temperatures.…”

Section: Indenter Controlmentioning

confidence: 99%

Effects of Testing Temperature on the Serration Behavior of an Al–Zn–Mg–Cu Alloy with Natural and Artificial Aging in Sharp Indentation

Yamada

Kami

Ogasawara

2020

Metals

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Serration phenomena, in which stress fluctuates in a saw-tooth shape, occur when a uniaxial test is performed on an aluminum alloy containing a solid solution of solute atoms. The appearance of the serrations is affected by the strain rate and temperature. Indentation tests enable the evaluation of a wide range of strain rates in a single test and are a convenient test method for evaluating serration phenomena. Previously, the serrations caused by indentation at room temperature were clarified using strain rate as an index. In this study, we considered ambient temperature as another possible influential factor. We clarify, through experimentation, the effect of temperature on the serration phenomenon caused by indentation. An Al–Zn–Mg–Cu alloy (7075 aluminum alloy) was used as the specimen. The aging phenomenon was controlled by varying the testing temperature of the solution-treated specimen. Furthermore, the material properties obtained by indentation were evaluated. By varying the testing temperature, the presence and amount of precipitation were controlled and the number of solute atoms was varied. Additionally, the diffusion of solute atoms was controlled by maintaining the displacement during indentations, and a favorable environment for the occurrence of serrations was induced. The obtained results reveal that the variations in the serrations formed in the loading curvature obtained via indentation are attributed to the extent of interaction between the solute atoms and the dislocations.

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