Stress corrosion cracking behaviour of 7xxx aluminum alloys: A literature review

The heat affected zone (HAZ) on the metal–inert gas (MIG) welding joint of 7N01 aluminium alloy was repaired by multipass narrow gap laser welding. The Y–X direction precracked three‐point bending sample was used in the alternate immersion test. The morphology of specimen surfaces demonstrated that the exfoliation corrosion in the HAZ after laser repair (HAZa) was more serious than that before laser repair (HAZb). The electrochemical impedance spectroscopy after different immersion corrosion time indicated that the HAZa and HAZb had similar corrosion potentials. However, the pitting corrosion resistance of HAZa was lower than that of HAZb at the beginning of exfoliation corrosion. The stress corrosion crack (SCC) of 7N01P‐T4 aluminium alloy displayed a multicrack source and an intergranular crack propagated along the rolling grain boundary under the test condition. An unusual method was taken to measure the length of SCC. The results showed that laser repairing did not weaken the stress corrosion resistance of the original joint.

normalM normalg normalZ n_{2} falsenormal(normali normaln normalG normalP normalz normalo normaln normale normals, η' normala normaln normald η) \to normalM g^{2 goodbreakprefixnormal+} + 2 normalZ n^{2 goodbreakprefixnormal+} + 6 e^{-},

normalA normall (normali normaln normals normalo normall normali normald normals normalo normall normalu normalt normali normalo normaln) goodbreaknormal\to normalA l^{3 goodbreakprefixnormal+} goodbreaknormal+ 3 e^{-},

…”

Section: Resultsmentioning

confidence: 99%

Section: Electrochemical Testmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of laser repairing on corrosion behaviour of metal–inert gas welding joint of 7N01 aluminium alloy

Huang

Chen

et al. 2019

“…The distribution of second phases has a significant influence on the corrosion behavior of high strength aluminum alloys . Figure shows the grain boundaries precipitates (GBPs) distribution using TEM technology.…”

Section: Discussionmentioning

confidence: 99%

Crack‐induced intergranular corrosion behavior of aerial aluminum alloy subjected to severe plastic deformation

et al. 2018

The influence of crack‐induced on the intergranular corrosion (IGC) behavior of aerial aluminum alloy subjected to severe plastic deformation (SPD) is investigated in this work. Addressing this problem, a particular SPD technology, namely elliptical cross‐sectioned spiral equal channel extrusion (ECSEE), is employed to prefabricate cracks. The microstructure, induced‐crack observation and IGC behavior of the ECSEE‐ed alloy are observed. ECSEE can significantly refine the grains, while lots of small and deep dimples as well as broken second‐phase particles appear on fracture surface. The formation mechanism of the fracture surface is revealed based on the observation of fracture morphology. A typical stress corrosion cracking characteristic is observed in IGC tested ECSEE‐ed alloy, and the corroded fracture consisted of higher volume fraction of brittle intergranular fractures that are made up of rockcandy‐like brittle and intergranular fracture. The mechanism of intergranular corrosion of dehiscence and cracking is determined considering the factors such as grain refinement, grain boundary precipitations, preexisted crack, and residual stress.

“…For instance, temperature, humidity, pH, and solute species influence the SCC behavior of A7N01 aluminum alloy . It has been reported that alloying elements influence the strength, grain size and orientation, grain boundaries, and residual stresses within the material, the SCC susceptibility depends on the elements content of the Zn and Mg . That is to say,when the Zn and Mg content is higher than 7% for aluminum alloys, the sensitivity of the alloy to SCC would increase considerably .…”

Section: Introductionmentioning

confidence: 99%

Stress corrosion cracking and corrosion fatigue cracking behavior of A7N01P‐T4 aluminum alloy

Shen

Chen

et al. 2017

A modified single edge notch tension (SENT) specimen exposed to saline environment was used to investigate the stress corrosion cracking and corrosion fatigue cracking behavior of A7N01P‐T4 aluminum alloy. The crack propagation rate was determined, the microstructure, crack growth path, and the fracture surfaces of specimens were examined by optical microscopy (OM) and scanning electron microscopy (SEM). The results showed that the stress corrosion cracking rate of A7N01P‐T4 alloy in 3.5% NaCl was three orders lower than that of corrosion fatigue crack propagation rate. Mg and Zn segregation at the grain boundaries increased the stress corrosion crack susceptibility. The grain orientation had a significant effect on the crack propagation performance, and the high angle grain boundaries were susceptible to cracking. Hydrogen embrittlement was the primary cause of stress corrosion crack and corrosion fatigue crack propagation.