scholarly journals Investigation of Stress Corrosion Cracking in Magnesium Alloys by Quantitative Fractography Methods

2017 ◽  
Vol 62 (2) ◽  
pp. 557-562 ◽  
Author(s):  
M. Sozańska ◽  
A. Mościcki ◽  
B. Chmiela
Keyword(s):  
Magnesium Alloy ◽  
Fracture Surface ◽  
Strain Rate ◽  
Stress Corrosion ◽  
Quantitative Evaluation ◽  
Stress Corrosion Cracking ◽  
Corrosion Cracking ◽  
Slow Strain Rate Test ◽  
Rate Test ◽  
We43 Magnesium Alloy

Abstract The article shows that the use of quantitative fracture description may lead to significant progress in research on the phenomenon of stress corrosion cracking of the WE43 magnesium alloy. Tests were carried out on samples in air, and after hydrogenation in 0.1 M Na2SO4 with cathodic polarization. Fracture surfaces were analyzed after different variants of the Slow Strain Rate Test. It was demonstrated that the parameters for quantitative evaluation of fracture surface microcracks can be closely linked with the susceptibility of the WE43 magnesium alloy operating under complex state of the mechanical load in corrosive environments. The final result of the study was the determination of the quantitative relationship between Slow Strain Rate Test parameters, the mechanical properties, and the parameters of the quantitative evaluation of fracture surface (microcracks).

Stress Corrosion Cracking Behaviour of Flux Bounded TIG Welded AA2219 T87 Aluminum Alloy in 3.5 Weight Percent NaCl Solution

2015 ◽  
Vol 766-767 ◽  
pp. 733-738
Author(s):  
A.V. Santhana Babu ◽  
P.K. Giridharan ◽  
A. Venugopal ◽  
P. Ramesh Narayanan ◽  
S.V.S. Narayana Murty
Keyword(s):  
Aluminum Alloy ◽  
Strain Rate ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Weight Percent ◽  
Corrosion Cracking ◽  
Slow Strain Rate Test ◽  
Nacl Solution ◽  
Test Technique ◽  
Rate Test

Limitation in penetration depth is a concern in conventional TIG welding. To improve penetration capability of TIG process, Flux Bounded TIG (FBTIG) has been developed. Stress corrosion cracking (SCC) behavior of FBTIG welds of aluminum alloy AA 2219 T87 is evaluated in 3.5 weight percent NaCl solution using Slow Strain Rate Test technique (SSRT) as per ASTM G129. SCC index defined as the ratio of the elongation of tensile tested specimen in NaCl to that of air is taken as a measure of the susceptibility to cracking. Based on the SCC index, it is concluded that the SCC resistance of FBTIG joints are good and comparable to that of conventional TIG welds.

Determination of Stress Corrosion Cracking Resistance of Al-Cu-Mg Alloys by Slow Strain Rate and Alternate Immersion Testing

CORROSION ◽  
1981 ◽  
Vol 37 (2) ◽  
pp. 98-103 ◽  
Author(s):  
Shantanu Maitra
Keyword(s):  
Strain Rate ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Corrosion Cracking ◽  
Slow Strain Rate ◽  
Test Method ◽  
Slow Strain Rate Test ◽  
Test Results ◽  
Alloy Plate ◽  
Rate Test

Abstract Increased artificial aging from the T351 temper to T851 temper is known to increase resistance to stress corrosion cracking (SCO for Al-Cu-Mg alloy 2124. A series of incrementally aged 2124 alloy plate was tested for resistance to SCC by the slow strain rate technique and by the conventional alternate immersion test method. It is shown that slow strain rate test results are in agreement with the conventional test results. Using fracture energy and other loss in ductility parameters to denote resistance to SCC, it has been shown that this technique can be used as a more accurate SCC test. SEM examinations of fracture surfaces confirm the SCC indices obtained by the slow strain rate test.

scholarly journals The Characterization of Stress Corrosion Cracking in the AE44 Magnesium Casting Alloy Using Quantitative Fractography Methods

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4125 ◽  
Author(s):  
Maria Sozańska ◽  
Adrian Mościcki ◽  
Tomasz Czujko
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
Stress Corrosion ◽  
Quantitative Evaluation ◽  
Stress Corrosion Cracking ◽  
Open Circuit ◽  
Corrosion Cracking ◽  
Slow Strain Rate Test ◽  
Time To Failure ◽  
Corrosive Environment

In this work an assessment of the susceptibility of the AE44 magnesium alloy to stress corrosion cracking in a 0.1M Na2SO4 environment is presented. The basic assumed criterion for assessing the alloy behavior under complex mechanical and corrosive loads is deterioration in mechanical properties (elongation, reduction in area, tensile strength and time to failure). The AE44 magnesium alloy was subjected to the slow strain rate test (SSR) in air and in a corrosive environment under open circuit potential (OCP) conditions. In each variant, the content of hydrogen in the alloy was determined. The obtained fractures were subjected to a quantitative evaluation by original fractography methods. It was found that under stress corrosion cracking (SCC) conditions and in the presence of hydrogen the mechanical properties of AE44 deteriorated. The change in the mechanical properties under SCC conditions in a corrosive environment was accompanied by the presence of numerous cracks, both on fracture surfaces and in the alloy microstructure. The developed method for the quantitative evaluation of cracks on the fracture surface turned out to be a more sensitive method, enabling the assessment of the susceptibility of AE44 under complex mechanical and corrosive loads in comparison with deterioration in mechanical properties. Mechanical tests showed a decrease in properties after SSRT tests in corrosive environments (UTS ≈ 153 MPa, ε = 11.2%, Z = 4.0%) compared to the properties after air tests (UTS ≈ 166 MPa, ε = 11.9%, Z = 7.8%) but it was not as visible as the results of quantitative assessment of cracks at fractures (number of cracks, length of cracks): after tests in corrosive environment (900; 21.3 μm), after tests in air (141; 34.5 μm). These results indicate that the proposed new proprietary test methodology can be used to quantify the SSC phenomenon in cases of slight changes in mechanical properties after SSRT tests in a corrosive environment in relation to the test results in air.

scholarly journals Investigation of Stress Corrosion Cracking Behaviour of Mg-Al-Zn Alloys in Different pH Environments by SSRT Method

2019 ◽  
Vol 17 (1) ◽  
pp. 972-979
Author(s):  
Recep Catar ◽  
Hikmet Altun
Keyword(s):  
Strain Rate ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Chloride Ions ◽  
Corrosion Cracking ◽  
Slow Strain Rate ◽  
Mg Alloys ◽  
Slow Strain Rate Test ◽  
Intergranular Stress Corrosion ◽  
Rate Test

AbstractIn this study, stress corrosion behaviors of AZ31, AZ61 and AZ91 Mg alloys which contain different amounts of Al were investigated under acidic, basic and neutral environments having chloride ions using Slow Strain Rate Test (SSRT) method. Stress corrosion indexes (ISCC), ultimate tensile strength (UTS) and elongation of AZ31, AZ61, and AZ91 Mg alloys were determined and compared. Slow strain rate test showed that three Mg alloys in basic environments were the least stress corrosion susceptible, while the most stress corrosion susceptible occurred in acidic environments. Also, it has been shown that the stress corrosion indexes of AZ91 Mg alloys are less than AZ31 and AZ61 Mg alloys in all environments. UTS and elongation of AZ61 Mg alloys were higher than those of AZ31 and AZ91 in all media. The fracture of surface images also examined in the scanning electron microscope (SEM) and both intergranular stress corrosion cracking (IGSCC) and transgranular stress corrosion cracking (TGSCC) were observed in all three alloys.

Sign in / Sign up

Export Citation Format

Share Document