Electron Microscopy of Stress-Corrosion Cracking in AM 350 Steel for a Supersonic Transport

2009 ◽  
pp. 10-10-14
Author(s):  
N. A. Tiner
Keyword(s):  
Electron Microscopy ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Corrosion Cracking ◽  
Supersonic Transport

scholarly journals Stress Corrosion Cracking in an Extruded Cu-Free Al-Zn-Mg Alloy

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1194
Author(s):  
Adrian Lervik ◽  
John C. Walmsley ◽  
Lars Lodgaard ◽  
Calin D. Marioara ◽  
Roy Johnsen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Aluminium Alloys ◽  
Double Cantilever Beam ◽  
Tensile Tests ◽  
Corrosion Cracking ◽  
Comprehensive Understanding ◽  
Beam Method ◽  
Scanning Electron

Stress corrosion cracking (SCC) in Cu-free Al-Zn-Mg (7xxx) aluminium alloys limits its use in many applications. In this work, we study in detail the microstructure of a peak and slightly overaged condition in an AA7003 alloy using transmission- and scanning electron microscopy in order to provide a comprehensive understanding of the microstructural features related to SCC. The SCC properties have been assessed using the double cantilever beam method and slow strain rate tensile tests. Grain boundary particles, precipitate free zones, and matrix precipitates have been studied. A difference in the SCC properties is established between the two ageing conditions. The dominating difference is the size and orientation of the hardening phases. Possible explanations correlating the microstructure and SCC properties are discussed.

Probing the stress corrosion cracking resistance of laser beam welded AISI 316LN austenitic stainless steel

2020 ◽  
pp. 095440622096563
Author(s):  
R Rajasekaran ◽  
AK Lakshminarayanan
Keyword(s):  
Electron Microscopy ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Laser Beam ◽  
Stress Corrosion ◽  
Base Metal ◽  
Stress Corrosion Cracking ◽  
Welded Joint ◽  
Corrosion Cracking ◽  
Time To Failure

The stress corrosion cracking (SCC) resistance of the laser beam welded (LBW) AISI 316LN austenitic stainless steel (SS) was assessed and compared to the base metal (BM). The weld joint was produced using a 2.5 kW laser power source at 1500 mm/min welding speed. Microstructural characterization of the base metal and weld joint were done by the following techniques: (i) Optical Microscopy (OM), (ii) Scanning Electron Microscopy (SEM) and (iii) Transmission Electron Microscopy (TEM). The primary mechanical properties such as strength, toughness and hardness of the welded joint were evaluated and compared with the base metal. Stress Corrosion Cracking (SCC) assessment was done in boiling 45 wt% MgCl2 solution at constant load condition as per American Society for Testing and Materials (ASTM) standard G36-94. From the SCC experiment data, steady-state elongation rate ([Formula: see text]), transition time ([Formula: see text]) and time to failure ([Formula: see text]) were found and generalized equations to predict the time to failure of the base metal and LBW joint were successfully derived. The passive film rupture mechanism majorly influenced the SCC failure for 316LN and welded joint. The formation of the discontinuous δ-ferrite network, residual stress and nitrogen pore nucleation at the fusion zone of the LBW joint deteriorated the SCC resistance. The metallographic and fractographic studies revealed brittle transgranular SCC failure of the base metal as well as the LBW joint in all the stress conditions.

Stress Corrosion Cracking of NiTi Orthodontic Wires in Sodium Fluoride Solution

2008 ◽  
Vol 32 ◽  
pp. 79-82 ◽  
Author(s):  
Xiao Ji Li ◽  
Jian Qiu Wang ◽  
En Hou Han ◽  
Wei Ke
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Corrosion Cracking ◽  
Slow Strain Rate Test ◽  
Orthodontic Wires ◽  
Fluoride Solution ◽  
Rate Test ◽  
Scanning Electron

The influence of fluoride on stress corrosion cracking (SCC) of NiTi orthodontic wires was investigated using slow strain rate test (SSRT) and scanning electron microscopy (SEM). The results indicated that fluoride significantly accelerated the stress corrosion cracking of NiTi orthodontic wires. The fractographies of NiTi orthodontic wires exhibited striation pattern.

Effect of Applied Potentials on Stress Corrosion Cracking Susceptibility of X80 Pipeline Steel in Simulated Soil Solution

2010 ◽  
Vol 146-147 ◽  
pp. 920-925 ◽  
Author(s):  
Yuan Cheng ◽  
Hong Ying Yu ◽  
Li Xin Zhang ◽  
Ying Wang ◽  
Xu Meng ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Stress Corrosion ◽  
Soil Solution ◽  
Stress Corrosion Cracking ◽  
Pipeline Steel ◽  
Corrosion Cracking ◽  
X80 Pipeline Steel ◽  
X80 Steel ◽  
Scanning Electron

The stress corrosion cracking susceptibility of X80 pipeline steel was investigated in a simulated soil solution using slow strain rate tensile (SSRT) tests. The different potentials were applied in the tests. The fracture surfaces were observed using scanning electron microscopy (SEM). The X80 steel was susceptible to SCC in simulated solution. The SCC susceptibility had no apparent change with the anodic potentials applied. The fracture mechanism was anodic dissolution. However, the SCC susceptibility increased with the decrease of the cathodic potentials obviously. The cracking was induced by the Hydrogen diffusing into the metal.

scholarly journals Korosi Retak Tegang pada Pipa Superheater Ketel Uap yang Baru Dibangun [Stress Corrosion Cracking of Cage Superheater Tubes of a Newly Built Boiler]

Metalurgi ◽  
2017 ◽  
Vol 32 (3) ◽  
pp. 123
Author(s):  
D.N. Adnyana
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Energy Dispersive Spectroscopy ◽  
Corrosion Cracking ◽  
Energy Dispersive ◽  
Composition Analysis ◽  
Superheater Tube ◽  
Scanning Electron

A number of cage superheater tubes of a newly built steam boiler have been leaking during boiler’s first start-up commissioning. Leaking occurred when the boiler had just reached a pressure of 23.7 barg and temperature 4050 C from the intended operating pressure of 53 barg and temperature of 4850C. Type of failure and factors that may have caused the leakage of the cage superheater tube are discussed in this paper. The metallurgical assessment was conducted by preparing a number of specimens from the as received leaked cage superheater tube. Various laboratory examinations were performed including macroscopic examination, chemical composition analysis, metallographic examination, hardness test and SEM (scanning electron microscopy) examination equipped with EDS (energy dispersive spectroscopy) analysis. Results of the metallurgical assessment obtained show that the leaked cage superheater tubes have been experiencing stress-corrosion cracking (SCC) caused by the combined effect of corrosion and tensile stress. The corrosion agent that may have been responsible for the occurrence of SCC in the tube was mostly due to caustic sodium (Na) and other elements in a lesser extent such as Ca, Cl, S and P.AbstrakSejumlah pipa penukar panas lanjut pada sebuah ketel uap yang baru dibangun diketemukan bocor selama operasi komisioning yang pertama. Kebocoran terjadi ketika ketel uap baru saja mencapai tekanan 23,7 barg dan temperatur 405 °C dari tekanan dan temperatur operasi yang direncanakan yaitu 53 barg dan 485 °C. Dalam makalah ini dibahas jenis kerusakan dan faktor-faktor yang kemungkinan telah menyebabkan terjadinya kebocoran pada pipa penukar panas lanjut tersebut. Penelitian/pengujian metalurgi telah dilakukan dengan mempersiapkan sejumlah benda uji yang diperoleh dari salah satu potongan pipa yang bocor tersebut. Berbagai pengujian laboratorium telah dilakukan meliputi: uji makro, analisa komposisi kimia, uji metalografi, uji kekerasan dan uji SEM (scanning electron microscopy) yang dilengkapi dengan analisis EDS (energy dispersive spectroscopy). Hasil penelitian/pengujian metalurgi yang diperoleh menunjukkan bahwa pipa penukar panas lanjut yang bocor tersebut telah mengalami retak korosi tegangan yang disebabkan oleh efek kombinasi antara korosi dan tegangan tarik. Unsur korosif yang kemungkinan dapat menimbulkan terjadinya retak korosi tegangan pada pipa penukar panas lanjut adalah kaustik sodium (Na) dan elemen-elemen lainnya pada tingkatan yang relatif rendah seperti Ca, Cl, S dan P. 

Nano-Scale Characterization of Stress Corrosion Cracking in a Failed Alloy C-276 Component

CORROSION ◽  
10.5006/3742 ◽  
2021 ◽  
Author(s):  
Des Williams ◽  
Jared Smith ◽  
Kevin Daub ◽  
Matthew Topping ◽  
Fei Long ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Ion Beam ◽  
Microstructural Analysis ◽  
Chemical Characterization ◽  
Corrosion Cracking ◽  
Corrosion Mechanism ◽  
Characterization Methods ◽  
Cracking Mode

A failure analysis was performed on an alloy C-276 pull rod which underwent unexpected brittle, intergranular fracture after exposure to 280°C-300°C aqueous solutions designed to replicate secondary side environments in nuclear energy systems: Pb-containing alkaline (pH300°C 8.5-9.5), and sulfate-containing acidic solutions (pH280°C 3-5). The component was characterized using advanced electron microscopy methods to demonstrate the benefits of these techniques for determining the nanoscale chemical, mechanical, and material factors contributing to failure, and to provide insight into the mechanisms of stress corrosion cracking (SCC) responsible for failure. Site-specific transmission electron microscopy specimens containing crack tips were prepared using focused ion beam. Nanoscale chemical characterization methods revealed that Pb was present in some oxidized regions of cracks, suggesting that the element may be inhibiting or impairing the passivity of the Cr-rich oxide. Complementary nanoscale microstructural analysis was performed. At an intergranular to transgranular cracking mode transition, it was observed that the transgranular crack (and corrosion process) propagated along the (110) crystallographic plane. Also, the cracking mode was highly dependent on the tensile stress direction relative to grain boundary orientation, the crystallographic orientation of grains and geometrically necessary dislocation structures. A comparison of results with proposed mechanisms for SCC of Ni alloys in similar environments are discussed; the highly directional nature of cracking is consistent with a slot-tunnel corrosion mechanism.

scholarly journals Effect of Natural Aging on the Stress Corrosion Cracking Behavior of A201-T7 Aluminum Alloy

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5631
Author(s):  
Mien-Chung Chen ◽  
Ming-Che Wen ◽  
Yang-Chun Chiu ◽  
Tse-An Pan ◽  
Yu-Chih Tzeng ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Natural Aging ◽  
Corrosion Cracking ◽  
Scanning Calorimetry ◽  
Cracking Behavior ◽  
Free Zone ◽  
Transmission Electron ◽  
Rate Testing

The effect of natural aging on the stress corrosion cracking (SCC) of A201-T7 alloy was investigated by the slow strain rate testing (SSRT), transmission electron microscopy (TEM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), conductivity, and polarization testing. The results indicated that natural aging could significantly improve the resistance of the alloys to SCC. The ductility loss rate of the unaged alloy was 28%, while the rates for the 24 h and 96 h aged alloys were both 5%. The conductivity of the as-quenched alloy was 30.54 (%IACS), and the conductivity of the 24 h and 96 h aged alloys were decreased to 28.85 and 28.65. After T7 tempering, the conductivity of the unaged, 24 h, and 96 h aged alloys were increased to 32.54 (%IACS), 32.52 and 32.45. Besides, the enthalpy change of the 24 h and 96 h aged alloys increased by 36% and 37% compared to the unaged alloy. The clustering of the solute atoms would evidently be enhanced with the increasing time of natural aging. Natural aging after quenching is essential to improve the alloy’s resistance to SCC. It might be due to the prevention of the formation of the precipitation free zone (PFZ) after T7 tempering.

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