Effect of retrogression and reaging treatments on the microstructure of Ai-7075-T651

Park, Joong Keun; Ardell, A.J.

doi:10.1007/bf02657792

Cited by 195 publications

(94 citation statements)

References 17 publications

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“…On the other hand, an increasing size of grain boundary precipitates has been proposed to explain the higher SCC resistance in the 7xxx series aluminum alloys. 5) The PFZ width and the size of the particles at the grain boundary of T7 temper, as shown in Fig. 6(d) and Fig.…”

Section: Microstructural Observationsmentioning

confidence: 92%

“…Consequently, the increase in SCC resistance of alloys was associated with a lower strength. It has been observed [3][4][5][6] that the main differences between the T6 and T7 tempers are related to the width of the precipitated free-zones, distribution of matrix precipitates, dislocation density, composition, size and distribution of grain boundary precipitates. These aspects of aluminum alloys are assumed to determine the susceptibility to SCC.…”

Section: Introductionmentioning

confidence: 99%

“…The main microstructural change after RRA temper is a very fine distribution of 0 precipitates in the matrix similar to T6 temper, and a larger size of precipitates on grain boundaries distributed similarly to T7 temper. 5,10,11) The combination microstructures could effectively improve both SCC resistance and strength. In addition, two-step aging treatments are often employed in high-strength 7xxx series aluminum alloys to obtained maximum precipitation hardening and better stress-corrosion resistance.…”

Section: Introductionmentioning

confidence: 99%

“…Several investigations have reported that the SCC mechanism involves anodic dissolution, [13][14][15] hydrogeninduced cracking (HIC), 5,13,[16][17][18] passive film rupture, 13,19) hydrogen embrittlement (HE), 14,15,20) magnesium segregation to grain boundaries [21][22][23] and a precipitate free zone (PFZ) along grain boundary. 24,25) However, the microstructural characteristics of Al-Zn-Mg high strength aluminum alloys are well known to have a strong influence not only on the mechanical properties but also on SCC susceptibility.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Microstructure on the Mechanical Properties and Stress Corrosion Cracking of an Al-Zn-Mg-Sc-Zr Alloy by Various Temper Treatments

Wang

Hsu

et al. 2007

Mater. Trans.

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The high strength Al-Zn-Mg alloy used in the aerospace industry is strengthened by coherent G.P. zones and semicoherent 0 phase. However, this series of aluminum alloys are susceptible to stress corrosion cracking (SCC), particularly when aged to the peak-aged state of T6 temper. In this study, the effect of microstructure on mechanical properties and stress corrosion cracking of the alloy was investigated for alloys tempered to T6, RRA, Two-Step and T7 conditions by tensile test in air, SCC test and polarization test in a 3.5%NaCl solution. It is shown that the improvement in SCC resistance correlates very well with the size of matrix precipitates and grain boundary precipitates. T7 temper can produce larger sizes of both the matrix precipitates and grain boundary precipitates than that of T6, RRA and Two-step tempers, causing a decrease in the length and density of dislocation lines, which results in the decrease of stress concentration at grain boundary and greatly improving the SCC resistance. The addition of Sc and Zr to high strength Al-Zn-Mg alloys has been found to simultaneously improve the tensile strength and SCC resistance.

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Section: Microstructural Observationsmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effects of Microstructure on the Mechanical Properties and Stress Corrosion Cracking of an Al-Zn-Mg-Sc-Zr Alloy by Various Temper Treatments

Wang

Hsu

et al. 2007

Mater. Trans.

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“…High-strength, precipitation hardened aluminium alloys such as AA7075 are widely used in aerospace industries in view of the good stress corrosion cracking (SCC) resistance in T7 temper conditions [1][2][3][4][5]. Although this treatment offered good improvement in the SCC resistance, localized corrosion such as pitting remains a problem in commercial aluminum alloys containing intermetallic phases such as Al 7 Cu 2 Fe, (Al,Cu) 6 (Fe,Cu), and Mg 2 Si.…”

Section: Introductionmentioning

confidence: 99%

Effect of Microstructure on the Localized Corrosion and Stress Corrosion Behaviours of Plasma-Electrolytic-Oxidation-Treated AA7075 Aluminum Alloy Forging in 3.5 wt. %NaCl Solution

Venugopal

Panda

Manwatkar

et al. 2012

International Journal of Corrosion

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The influence of metallurgical heterogeneities such as coring and intermetallic phases on the corrosion and stress corrosion cracking behaviours of AA7075 aluminium alloy forging was examined in 3.5 wt. % NaCl solution with and without plasma electrolytic oxidation coating. Electrochemical test results demonstrated significant improvement in the corrosion resistance of the alloy after PEO coating. Stress corrosion results show that the metallurgical heterogeneities resulted in a loss in elongation of the uncoated sample in NaCl (11.5%) when compared to the one tested in air (12.9%). The loss in elongation of the uncoated sample was shown to be due to localized corrosion-assisted mechanical cracking rather than true stress corrosion based on preexposure tensile tests followed by posttest metallographic observation of the stress corrosion tested samples. This was further confirmed by the fractographic examination of the failed samples, which exhibited a typical ductile cracking morphology for all the coated and uncoated specimens.

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A Novel Solution Heat Treatment of 7075‐Type Alloy

Ibrahim¹,

Samuel²,

Alkahtani³

et al. 2013

Light Metals 2013

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Effect of retrogression and reaging treatments on the microstructure of Ai-7075-T651

Cited by 195 publications

References 17 publications

Effects of Microstructure on the Mechanical Properties and Stress Corrosion Cracking of an Al-Zn-Mg-Sc-Zr Alloy by Various Temper Treatments

Effects of Microstructure on the Mechanical Properties and Stress Corrosion Cracking of an Al-Zn-Mg-Sc-Zr Alloy by Various Temper Treatments

Effect of Microstructure on the Localized Corrosion and Stress Corrosion Behaviours of Plasma-Electrolytic-Oxidation-Treated AA7075 Aluminum Alloy Forging in 3.5 wt. %NaCl Solution

A Novel Solution Heat Treatment of 7075‐Type Alloy

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