Ri. Stephens et al., CORROSION-FATIGUE OF AZ91E-T6 CAST MAGNESIUM ALLOY IN A 3.5 PERCENT NACL AQUEOUS ENVIRONMENT, Journal of engineering materials and technology, 117(3), 1995, pp. 293-298
The objective of this research was to obtain and compare constant and
variable amplitude fatigue behavior of AZ91E-T6 cast magnesium alloy i
n both an air and 3.5 percent NaCl aqueous corrosive environment. An a
dditional objective was to determine if commonly used models that desc
ribe fatigue behavior and fatigue life are applicable to this material
and test environment. Fatigue tests included constant amplitude strai
n-controlled low cycle fatigue with strain ratio, R, equal to 0, -1 an
d -2, Region II constant amplitude fatigue crack growth with load rati
o, R, equal to 0.05 and 0.5 and variable amplitude fatigue tests using
keyhole notched specimens. In all fatigue tests, the corrosion enviro
nment was significantly detrimental relative to the air environment. M
ean strains influenced fatigue life only if accompanied by significant
mean stress. The Morrow and Smith, Watson, and Topper mean stress mod
els provided both accurate and inaccurate fatigue life calculations. L
ikewise, variable amplitude fatigue life calculations using the local
strain approach and based upon the formation of a 1 mm crack at the ke
yhole notch were both accurate and fairly inaccurate depending on the
specific model used.