Stress Corrosion Cracking of Magnesium Die Casting Alloys

1988 ◽  
Vol 125 ◽  
Author(s):  
William K. Miller
Keyword(s):  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Die Casting ◽  
Corrosion Cracking ◽  
Film Rupture ◽  
Partial Immersion ◽  
Casting Alloys ◽  
Hydrogen Assisted Cracking ◽  
The Subject ◽  
Magnesium Die Casting

ABSTRACTContrary to limited published information on the subject, magnesium die casting alloys are shown to be susceptible to stress corrosion cracking (SCC), requiring only partial immersion in distilled water. Also described is evidence that this SCC results from a cathodic process, with perhaps hydrogen-assisted cracking and film rupture both playing roles.

Intergranular Stress Corrosion Cracking Damage Model: An Approach and Its Development for Alloy 600 in High-Purity Water

CORROSION ◽  
1986 ◽  
Vol 42 (2) ◽  
pp. 99-105 ◽  
Author(s):  
Y. S. Garud ◽  
A. R. McIlree
Keyword(s):  
Strain Rate ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
High Purity ◽  
Corrosion Cracking ◽  
Model Parameters ◽  
Alloy 600 ◽  
Intergranular Stress Corrosion ◽  
Film Rupture ◽  
Intergranular Stress Corrosion Cracking

Abstract A logical approach to quantitative modeling of intergranular stress corrosion cracking (IGSCC) is presented. The approach is based on the supposition (supported partly by experimental and field observations, and by a related plausible underlying mechanism) that strain rate is a key variable. The approach is illustrated for the specific case of NiCrFe Alloy 600 in high-purity water. Model parameters are determined based on the constant stress IGSCC data (between 290 and 365 C) assuming a power law relation between the damage and the nominal strain rate. The model may be interpreted in terms of a film rupture mechanism of the corrosion process. The related mechanistic considerations are examined for the specific case. Resulting calculations and stress as well as temperature dependence are shown to be in good agreement with the data. More data are needed for further verification under specific conditions of interest.

Film Rupture Mechanism for Stress Corrosion Cracking of AISI 304 in HCl Solutions

CORROSION ◽  
1975 ◽  
Vol 31 (10) ◽  
pp. 352-357 ◽  
Author(s):  
J. R. GALVELE ◽  
S. B. de WEXLER ◽  
I. GARDIAZABAL
Keyword(s):  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Corrosion Cracking ◽  
Film Rupture ◽  
Aisi 304 ◽  
Rupture Mechanism

Deformation of Iron Oxides Formed in Caustic Electrolyte

CORROSION ◽  
1976 ◽  
Vol 32 (10) ◽  
pp. 411-414 ◽  
Author(s):  
RONALD B. DIEGLE ◽  
DAVID A. VERMILYEA
Keyword(s):  
Stress Corrosion ◽  
Iron Oxides ◽  
Stress Corrosion Cracking ◽  
Fracture Strain ◽  
Film Growth ◽  
Corrosion Cracking ◽  
Growth Potential ◽  
Film Rupture ◽  
Potential Region ◽  
Rupture Model

Abstract Straining electrode experiments have shown that Fe3O4 grown on iron in NaOH electrolyte at 85 C fractures at strains ranging from less than about 3 × 10−4 to 3 × 10−3. Films less than 100 Å thick fracture at the smaller strain, whereas 1 μm films fracture at the larger value. Fracture strain is potential dependent, being least in the active-passive potential region of polarization behavior and increasing as the film growth potential becomes more anodic. These observations were used to interpret the potential dependence of caustic stress corrosion cracking (SCC) according to a film rupture model.

Some Electrochemical Aspects of the Stress Corrosion Cracking of Steels in Liquid Ammonia Environments

CORROSION ◽  
1976 ◽  
Vol 32 (4) ◽  
pp. 139-143 ◽  
Author(s):  
D. C. DEEGAN ◽  
B. E. WILDE ◽  
R. W. STAEHLE
Keyword(s):  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Liquid Ammonia ◽  
Corrosion Cracking ◽  
Surface Films ◽  
Test Results ◽  
Film Rupture ◽  
Electrode Potentials ◽  
Rupture Model

Abstract Some electrochemical aspects of the stress corrosion cracking (SCC) behavior of ASTM A517 Grade F steel in liquid ammonia environments at 25 C have been studied. Electrode potentials were measured during SCC tests by means of thallium/saturated thallous chloride/ammonia reference half cell. The effects of controlled additions of oxygen and nitrogen (species in combination known to cause SCC), as well as the inhibitive properties of water, were investigated. The test results indicate that an oxygen-bearing film forms on the metal surface after which passive-range potentials near +400 mV are observed. Under film-free conditions, potentials near −150 mV were measured. From coulometric measurements, film thicknesses were estimated at 3 to 5 monolayers coverage. SCC in this system can best be described by a film rupture model in which crack initiation occurs at local sites of film breakdown due to straining. The role of water as an inhibitor is to assist in the repassivation of the surface films, as indicated by the fact that water additions promote more noble potentials (+500 mV).

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