Effect of grain boundary characteristics on intergranular corrosion resistance of 6061 aluminum alloy extrusion

Minoda, Tadashi; Yoshida, Hideo

doi:10.1007/s11661-002-0274-3

Cited by 128 publications

(42 citation statements)

References 3 publications

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“…The reason why the warm rolled sheets containing zirconium have good resistance to SCC may be derived from its microstructure. In the previous study on AA6061 alloy extrusions, 13) it was suggested the formation of a precipitate free zone (PFZ) is restrained at a low angle boundary, which leads to high resistance to intergranular corrosion. Figure 11 shows TEM images of the samples in T6 condition and Kikuchi patterns derived from two grains facing each other across a grain boundary.…”

Section: Discussionmentioning

confidence: 99%

Improvement of Mechanical Properties of 7475 Based Aluminum Alloy Sheets by Controlled Warm Rolling

et al. 2004

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An attempt was made to refine the grain structure of 200 mm wide sheets of AA7475 based aluminum alloys containing zirconium by employing a new warm rolling method under the control of both roll temperature and material temperature. The warm rolled sheets as solution heat treated had subgrain structures through the thickness with a high proportion of low angle boundary less than 15. The average subgrain diameter was approximately 3 mm. The strength of the warm rolled sheets in T6 condition was about 10% higher than that of conventional AA7475 alloy sheets produced by cold rolling. As the most remarkable point in the warm rolled sheets, the high Lankford (r) value of 3.5 was measured in the orientation of 45 to rolling direction, with the average r-value of 2.2. The high r-value would be derived from well developedfiber textures, especially with the strong f011gh211i Brass component. The warm rolled sheets also had high resistance to SCC. From Kikuchi lines analysis and TEM images, it was found that PFZs were hardly formed along the low angle boundaries of the warm rolled sheets in T6 condition. This would be a factor to lead to the improvement of resistance to SCC because of reducing the difference in electrochemical property between the grain boundary area and the grain interior.

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Section: Discussionmentioning

confidence: 99%

Improvement of Mechanical Properties of 7475 Based Aluminum Alloy Sheets by Controlled Warm Rolling

et al. 2004

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“…Due to the pinning effect of nano-sized Al 3 (Sc, Zr) particles on the movement of the grain boundaries [26], dynamic recrystallization of Al-Zn-Mg alloy during hot extrusion is inhibited. Compared with high-angle recrystallization grain boundary, low-angle subgrain boundary with lower grain boundary energy inhibits the formation of GBPs and PFZ [13], so Sc addition reduces the width of PFZ and transforms GBPs from continuous distribution into interrupted distribution for Al-Zn-Mg alloy. Figure 3 gives stress-strain curves of two aged alloys tested at a strain rate of 5 × 10 −6 s −1 in different corrosive environments.…”

Section: Methodsmentioning

confidence: 99%

“…7xxx series alloys are mainly applied in the form of rolled plates or extruded sections, and the static or dynamic recrystallization is easy to occur during hot working and heat treatment. Compared with low-angle grain boundary, high-angle recrystallization grain boundary with higher grain boundary energy promotes the nucleation and growth of grain boundary precipitates (GBPs) [13]. Under peak-aged condition, the GBPs distributed continuously along recrystallization grain boundary accelerate corrosion crack propagation [14,15].…”

Section: Introductionmentioning

confidence: 99%

Influence of Scandium Addition on Stress Corrosion Cracking Susceptibility of Al-Zn-Mg Alloy in Different Corrosive Environments

Jiang

Yan

et al. 2018

Metals

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Stress corrosion cracking (SCC) susceptibilities of Al-Zn-Mg alloys without and with Scandium addition were evaluated in 3.5% NaCl solution at different pH and different strain rate, using slow strain rate test technique. The results indicate that Sc addition reduces grain size and width of precipitation free zones, and transforms grain boundary precipitates from continuous distribution into interrupted distribution by inhibiting recrystallization. In solution at pH 1, pH 3 and pH 7, Sc addition reduces the degree of localized corrosion of alloy surface and SCC susceptibility of Al-Zn-Mg alloy. However, in solution at pH 10 and pH 12, grain refinement significantly promotes the diffusion of hydrogen atoms into matrix, thus Sc addition increases SCC susceptibility of Al-Zn-Mg alloy. Under different strain rate conditions, Sc addition can all reduce SCC susceptibility of Al-Zn-Mg alloy in solution at pH 1, pH 3 and pH 7, and can all increase SCC susceptibility of Al-Zn-Mg alloy in solution at pH 10 and pH 12. As a result, Sc modified Al-Zn-Mg alloy in practical applications should be avoided in alkaline environments.

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“…2b shows that the corrosion is intergranular and occurs much more on the precipitates free zones. T. Minoda et al [11] reported that there is dissolution of the zones PFZs because of the difference between the potential of these zones PFZs and the grain wedges of the precipitates in the matrix. Fig.…”

Section: Experimental Materials and Methodsmentioning

confidence: 99%

EFFECT OF HEAT TREATMENT ON THE CORROSION BEHAVIOR OF Al-10%WT Mg ALLOYS

Zermane¹,

Chala²,

Belahssen³

2017

Acta Metall Slovaca

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In the present investigation, the effect of heat treatment on the electrochemical behavior of Al-10% wt Mg alloy in 3.5% wt NaCl is studied by different electrochemical techniques such as polarization technique (Tafel plot) and electrochemical impedance spectroscopy. It has been shown that the corrosion resistant of the alloy decreased with the ageing treatment at 250 °C for 24 h. However, this latter increased with naturally ageing. The SEM (electron microscope) and Energy Dispersive EDS characterization have shown that the alloy with the two treatments of ageing became susceptible to the pitting corrosion.Keywords: Al-Mg alloy; ageing treatment; corrosion; microstructure IntroductionThe addition of selected elements to pure aluminum enhances its; mechanical, physical, and chemical properties.The addition of magnesium to aluminium gives good hardness, good weldability and favorable corrosion resistance. Alloys in which magnesium is the primary alloying element are used in ship hulls, passage boards and other products exposed to marine environments because of their excellent corrosion resistance [1,2]. Non-heat treatable Al-Mg alloys (5xxx series) have better formability but; on the other hand, they are not precipitation hardenable, and that may limit their use in certain areas, and heat treatment provides alloys with interesting physical and mechanical properties [3]. Increasing the percentage of Mg in the aluminium matrix gives an alloy with good hardness, but very susceptible to intergranular corrosion and stress corrosion [2]. However, a percentage greater than 3%wt Mg in the aluminium α matrix favours the precipitation of the β (Al3Mg2) phase on the grain boundary and the latter is anodic with respect to the aluminium matrix and corrodes preferentially [4]. The corrosion behavior of Al-Mg alloys is controlled by the morphology and distribution of its precipitates on the grain boundary [2,3]. It was discovered that the kind, size, and distribution of the intermetallic phases located along the grain boundaries are regarded as the main factors responsible for the susceptibility to stress corrosion cracking [5]. A thin layer of invisible oxide forms immediately when the aluminium surfaces are exposed to the atmosphere, which protects the metal from further oxidation. Therefore the alloy becomes passive. But this behaviour can be interrupted by the existence of pitting corrosion, which produces a severe problem [2,6]. In the present work, the electrochemical behaviour of the Al-10%wtMg alloy was investigated at two different ageing treatments by means of polarisation curves, electrochemical impedance spectroscopy, characterised by SEM and EDS.

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Effect of grain boundary characteristics on intergranular corrosion resistance of 6061 aluminum alloy extrusion

Cited by 128 publications

References 3 publications

Improvement of Mechanical Properties of 7475 Based Aluminum Alloy Sheets by Controlled Warm Rolling

Improvement of Mechanical Properties of 7475 Based Aluminum Alloy Sheets by Controlled Warm Rolling

Influence of Scandium Addition on Stress Corrosion Cracking Susceptibility of Al-Zn-Mg Alloy in Different Corrosive Environments

EFFECT OF HEAT TREATMENT ON THE CORROSION BEHAVIOR OF Al-10%WT Mg ALLOYS

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