Corrosion Fatigue of AZ91E-T6 Cast Magnesium Alloy in a 3.5 Percent NaCl Aqueous Environment

1995 ◽  
Vol 117 (3) ◽  
pp. 293-298 ◽  
Author(s):  
R. I. Stephens ◽  
C. D. Schrader ◽  
K. B. Lease
Keyword(s):  
Fatigue Life ◽  
Magnesium Alloy ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Mean Stress ◽  
Constant Amplitude ◽  
Variable Amplitude ◽  
Cast Magnesium Alloy ◽  
Cast Magnesium ◽  
Variable Amplitude Fatigue

The objective of this research was to obtain and compare constant and variable amplitude fatigue behavior of AZ91E-T6 cast magnesium alloy in both an air and 3.5 percent NaCl aqueous corrosive environment. An additional objective was to determine if commonly used models that describe fatigue behavior and fatigue life are applicable to this material and test environment. Fatigue tests included constant amplitude strain-controlled low cycle fatigue with strain ratio, R, equal to 0, −1 and −2, Region II constant amplitude fatigue crack growth with load ratio, R, equal to 0.05 and 0.5 and variable amplitude fatigue tests using keyhole notched specimens. In all fatigue tests, the corrosion environment was significantly detrimental relative to the air environment. Mean strains influenced fatigue life only if accompanied by significant mean stress. The Morrow and Smith, Watson, and Topper mean stress models provided both accurate and inaccurate fatigue life calculations. Likewise, variable amplitude fatigue life calculations using the local strain approach and based upon the formation ofal mm crack at the keyhole notch were both accurate and fairly inaccurate depending on the specific model used.

Application and Verification of Fatigue Life Calculation Methods for AZ91E-T6 Cast Magnesium Alloy Under Variable Amplitude Loading

1993 ◽  
Vol 115 (4) ◽  
pp. 385-390 ◽  
Author(s):  
S. N. Perov ◽  
V. V. Ogarevic ◽  
R. I. Stephens
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Magnesium Alloy ◽  
Fatigue Crack Initiation ◽  
Calculation Methods ◽  
Sand Cast ◽  
Variable Amplitude Loading ◽  
Variable Amplitude ◽  
Cast Magnesium Alloy ◽  
Cast Magnesium

The goal of this research was to determine the applicability of commonly used fatigue life calculation methods for variable amplitude loading with sand cast AZ91E-T6 magnesium alloy using notched “keyhole” specimens. Commercially available fatigue life calculation software packages were used to calculate the fatigue crack “initiation” life (1 mm crack) and fatigue crack growth life corresponding to the experiments. The resulting correlation between experimental and calculated fatigue lives ranged from good to poor, and from conservative to nonconservative, depending on the analysis method used. It was shown that these fatigue life calculation methods can be used with this sand cast magnesium alloy but with certain apprehension.

scholarly journals Experimental Study on Variable-Amplitude Fatigue of Welded Cross Plate-Hollow Sphere Joints in Grid Structures

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Jin-Feng Jiao ◽  
Hong-Gang Lei ◽  
Y. Frank Chen
Keyword(s):  
Fatigue Life ◽  
Hollow Sphere ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Metallographic Analysis ◽  
Variable Load ◽  
Random Loading ◽  
Variable Amplitude ◽  
Different Types ◽  
Variable Amplitude Fatigue

The fatigue stress amplitude of the welded cross plate-hollow sphere joint (WCPHSJ) in a grid structure varies due to the random loading produced by suspending cranes. A total of 14 specimens considering three different types of WCPHSJs were prepared and tested using a specially designed test rig. Four typical loading conditions, “low-high,” “high-low,” “low-high-low,” and “high-low-high,” were first considered in the tests to investigate the fatigue behavior under variable load amplitudes, followed by metallographic analyses. The experimental and metallographic analysis results provide a fundamental understanding on the fatigue fracture form and fatigue mechanism of WCPHSJs. Based on the available data from constant-amplitude fatigue tests, the variable-amplitude fatigue life of the three types of WCPHSJs was estimated using the Miner rule and Corten-Dolan theory. Since both accumulative damage theories yield virtually same damaging results, the Miner rule is hence suggested to estimate the fatigue life of WCPHSJs.

Fatigue of AZ91E-T6 Cast Magnesium Alloy

1993 ◽  
Vol 115 (4) ◽  
pp. 391-397 ◽  
Author(s):  
D. L. Goodenberger ◽  
R. I. Stephens
Keyword(s):  
Fatigue Crack ◽  
Magnesium Alloy ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Mean Stress ◽  
Cycle Fatigue ◽  
Cast Magnesium Alloy ◽  
Cast Magnesium

The purpose of this research was to obtain room temperature fatigue behavior of AZ91E-T6 cast magnesium alloy and to determine if commonly used models that depict fatigue behavior are applicable to this cast alloy. Axial strain-controlled fatigue behavior using cylindrical specimens were employed to determine low cycle fatigue behavior with strain ratios R = εmin/εmax = 0, −1, and −2. The conventional log-log total strain low cycle fatigue model properly represented the R = −1 axial fatigue data. Significant mean stress relaxation occurred for all R = 0 and −2 axial fatigue tests. However, for the smaller strain amplitude tests with R = 0, sufficient mean stresses were retained such that fatigue life was reduced. The mean strains/stresses had little influence on the cyclic stress-strain curve which exhibited cyclic strain hardening. Mean stress effects were analyzed using the Morrow, SWT and Lorenzo-Laird models and similar, but oftentimes nonconservative, calculations resulted. Region I and II fatigue crack growth behavior was determined using C(T) speciments with load ratios R = Pmin/Pmax = 0.05 and 0.5. Values of ΔKth and (ΔKth)eff were less than 1.5 MPa m and the Paris equation slopes were between 3.3 and 3.9. Quasi-cleavage was predominant for both fatigue crack growth and final fracture regions. The commonly used low cycle fatigue and fatigue crack growth models appear to reasonably represent most of the results with this AZ91E-T6 cast magnesium alloy.

Fatigue of Stabilized SS and 316 NG Alloy in PWR Environment

2006 ◽  
Author(s):  
Jussi P. Solin
Keyword(s):  
Stainless Steels ◽  
Fatigue Tests ◽  
Test Results ◽  
Constant Amplitude ◽  
Low Oxygen ◽  
Variable Amplitude ◽  
Variable Amplitude Fatigue ◽  
Reduction Factors

Strain controlled constant and variable amplitude fatigue tests for 316NG and Titanium stabilized stainless steels in low oxygen PWR waters were performed. The stabilized steel has been plant aged for 100 000 hours. Constant amplitude test results at 0,01 Hz sinusoidal straining comply with predicted lives according to the Fen approach for both materials. Spectrum straining both in air and in environment caused predicted life reduction factors (about 3) for the stabilized steel, but for the 316NG steel spectrum straining in environment resulted to a larger reduction in life.

scholarly journals Multiaxial fatigue behavior of 2618 aluminum alloy

2019 ◽  
Vol 300 ◽  
pp. 09003
Author(s):  
Benaïssa Malek ◽  
Catherine Mabru ◽  
Michel Chaussumier
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Life ◽  
Internal Pressure ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Multiaxial Fatigue ◽  
Mean Stress ◽  
Research Project ◽  
Pressure Tests

The purpose of the present research project is to study multiaxial fatigue behavior of 2618 alloy. The influence of mean stress on the fatigue behavior under tension and torsion is particularly investigated. Fatigue tests under combined tensile-torsion, in or out of phase, as well as combined tensile-torsion-internal pressure tests have also been conducted. Multiaxial fatigue results are analyzed according to Fatemi-Socie criterion to predict the fatigue life.

Investigations on Fatigue Properties of Die Cast Magnesium Alloy AZ91HP at Very High Cycles

2007 ◽  
Vol 353-358 ◽  
pp. 235-238
Author(s):  
Tang Li ◽  
Qing Yuan Wang ◽  
Q.F. Dou ◽  
Chong Wang ◽  
M.R. Sriraman
Keyword(s):  
Magnesium Alloy ◽  
Fatigue Cracks ◽  
Ambient Air ◽  
Fatigue Tests ◽  
Fatigue Properties ◽  
Loading Frequency ◽  
Die Cast ◽  
Cast Magnesium Alloy ◽  
Cast Magnesium ◽  
Very High

Very high cycle fatigue (VHCF) properties of high-pressure die cast Magnesium alloy AZ91HP have been investigated. Ultrasonic fatigue tests up to 109 cycles were conducted at the loading frequency of 20 kHz, under R=-1 condition and in ambient air. The experimental results show that specimens fail even after 107 cycles although the scatter seems to be large probably due to the presence of materials defects. However, there seems to be a fatigue limit at about 109 cycles. The fractures contain typical brittle features, with the fatigue cracks seen to initiate from the porosity in the material, either from the surface or beneath.

Constant and Variable Amplitude Fatigue Behavior of Five Cast Steels at Room Temperature and −45°C

1984 ◽  
Vol 106 (1) ◽  
pp. 25-37 ◽  
Author(s):  
R. I. Stephens ◽  
J. H. Chung ◽  
A. Fatemi ◽  
H. W. Lee ◽  
S. G. Lee ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Room Temperature ◽  
Fatigue Behavior ◽  
Growth Behavior ◽  
Constant Amplitude ◽  
Variable Amplitude ◽  
Cast Steels ◽  
Variable Amplitude Fatigue

A comprehensive fatigue program was undertaken at room temperature and −45°C (−50°F) for five representative carbon or low alloy cast steels. Constant amplitude low and high cycle axial fatigue behavior, cyclic stress-strain behavior, constant-amplitude fatigue-crack-growth behavior and variable-amplitude fatigue-crack-initiation and -growth behavior were determined. The fatigue resistance at low temperature was usually equal to or better than at room temperature except for one material under variable amplitude fatigue crack growth conditions. SEM analysis revealed similar fatigue crack growth mechanisms at both room and low temperature, even though some tests were well below the NDT temperature. Most fatigue resistance for the five cast steels was consistent with that for wrought steels. Fatigue test procedures generally developed with wrought steels were completely satisfactory for these cast steels.

Effect of Solid Solution Treatment on Fatigue Behavior of Cast Magnesium Alloy

2013 ◽  
Vol 281 ◽  
pp. 436-440
Author(s):  
You Yang ◽  
Hua Wu ◽  
Zhao Feng Xuan
Keyword(s):  
Solid Solution ◽  
Magnesium Alloy ◽  
Fatigue Fracture ◽  
High Cycle Fatigue ◽  
Fatigue Behavior ◽  
Solution Treatment ◽  
Cycle Fatigue ◽  
Solid Solution Treatment ◽  
Cast Magnesium Alloy ◽  
Cast Magnesium

The effects of solid solution treatment on high cycle fatigue behavior of cast magnesium alloy AZ91D were investigated using an up-and-down load method. High cycle fatigue tests were carried out up to 107cycles at a stress ratio R=0.1 and frequency of 90Hz on specimens using a high frequency fatigue machine. The results showed that the fatigue strength of cast AZ91D magnesium alloy increase from 54.5Mpa to 71.5Mpa after solid solution treatment (T4) at 415°C, keeping temperature 16hours. The micro-fatigue fracture surface of alloy included fatigue initiation area, fatigue crack propagation area and fatigue fracture area. Fatigue crack of the alloys initiate principally at inclusions and shrinks under subsurface. The fatigue fracture of test specimens show the rupture characteristics of quasi-cleavage(as-cast alloy) and toughness(T4 alloy), respectively.

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