Study on double peaks aging strengthening and stress corrosion cracking behaviour of 7075 aluminium alloy

The double cantilever beam has been widely used in the past and has proved one of the most popular designs for measuring the growth rate of stress corrosion cracks in materials. In this study, the double cantilever beam specimens were used to study the effect of tensile loading on stress corrosion cracking behaviour in aluminium alloy 7075(W). Cracks initiated readily in 3.5%NaCl solution with tensile loading conditions. Stress Corrosion Cracking (SCC) development was found to follow an intergranular path, which strongly depended on microstructure of material. Tests also were carried out to measure the threshold stress intensity, KISCC, which SCC would not occur. The SCC test was explained by an active path mechanism due to the galvanic interaction between grain boundary precipitates and adjacent precipitate-free zones. Crack lengths were measured with an eddy current bore probe and confirmed by optical metallography. The data from the eddy current tests on real stress corrosion cracks were used to construct an eddy current calibration curve for predicting stress corrosion crack lengths of aluminium alloy 7075(W).

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Effect of Heat Treatment on Mechanical Properties and Susceptibility to Stress Corrosion Cracking of Aluminium Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.845.178 ◽

2013 ◽

Vol 845 ◽

pp. 178-182 ◽

Cited By ~ 2

Author(s):

Zahari Nur Ismarrubie ◽

K.W. Loh ◽

Hanafiah Yussof

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Aluminium Alloy ◽

Stress Corrosion ◽

Stress Corrosion Cracking ◽

Corrosion Cracking ◽

Tension Stress ◽

Nacl Solution ◽

Direct Tension ◽

Retrogression And Reaging

The effect of the retrogression and reaging (RRA) heat treatment on the correlation between microstructure, mechanical properties and susceptibility to stress corrosion cracking (SCC) of the 6061-T6 aluminium alloy in dry air and sprayed in 3.5% NaCl solution has been studied. The as-received T6 alloy was subjected to retrogression at temperature 200°C for 10 minutes, quenching for 30 seconds and reaging at temperature 180°C for 24 h. In this study, the effect of RRA on mechanical properties of the as-received 6061-T6 alloy was investigated by tensile test in air and sprayed in 3.5% NaCl solution. Alternate immersion preparation was conducted to expose the as-received 6061-T6 alloys and RRA heat treated alloys into the corrosive environment, 3.5% NaCl solution for 20 days. The susceptibility to SCC was investigated by direct tension stress-corrosion (DTSC) tests sprayed in a 3.5% NaCl solution at crosshead speed of 0.2 mm/min; the loss of elongation (ELloss) was taken into account for the susceptibility to SCC. Generally, the RRA heat treatment improves the mechanical properties including yield strength, ultimate tensile strength and ductility. On the other hand, the RRA heat treatment decreases the susceptibility to SCC.

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The study of variations in stress corrosion cracking velocities in aluminium alloy 7075-T651 by acoustic emission

Materials Science and Engineering ◽

10.1016/0025-5416(83)90057-5 ◽

1983 ◽

Vol 58 (2) ◽

pp. L5-L8 ◽

Cited By ~ 5

Author(s):

J.I. Dickson ◽

P. Martin ◽

J.-P. Baïlon

Keyword(s):

Acoustic Emission ◽

Aluminium Alloy ◽

Stress Corrosion ◽

Stress Corrosion Cracking ◽

Corrosion Cracking

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A Study on the Corrosion Behaviour of Aluminium Alloy 2014 T-651 Friction Stir Welds Using Stress Corrosion Cracking

Volume 14: Emerging Technologies; Safety Engineering and Risk Analysis; Materials: Genetics to Structures ◽

10.1115/imece2015-53258 ◽

2015 ◽

Author(s):

Thamilarasan Kollapuri ◽

Madhanagopal Manoharan ◽

Rajendra Boopathy Sadayan ◽

Rama Koteswara Rao Sajja

Keyword(s):

Aluminium Alloy ◽

Stress Corrosion ◽

Stress Corrosion Cracking ◽

Corrosion Behaviour ◽

Fracture Morphology ◽

Corrosion Cracking ◽

Al Alloy ◽

Time To Failure ◽

Friction Stir ◽

Heat Treated

Stress Corrosion Cracking (SCC) is the initiation and slow growth of cracks under the influence of tensile stresses and aggressive corrosion environment. Al alloy 2014 T 651 was solution heat treated and stress-relieved. In the present work, Stress Corrosion Cracking (SCC) experimental arrangement has been used to test the severity of aluminium alloys under particular environmental conditions. Sound welds were obtained with Friction Stir Welding at rotational speed of 800 rpm and welding speed of 200 mm/min. Friction Stir Welds were cut into standard tensile specimens as per ASTM E8 standards. Time to failure of the welds were obtained using 3.5 wt% NaCl solution at pH 10 in 0.7 and 1.1 yields by Stress Corrosion Cracking. Vickers micro-hardness was taken along various regions of the weld. Optical micro-graphs and scanning electron fractographs were taken to analyse the fracture behavior and fracture morphology of Friction Stir Welded aluminium alloy specimens, subjected to Stress Corrosion Cracking.

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