An experimental method of evaluating the fatigue behavior of alloys in different particle environments was designed, and the effects of four kinds of particles (i.e., graphite, CaO, Al2O3, and MnO2) on the crack propagating behavior of 7N01-T6 behaviour alloys were investigated. The results show that the particles deposited on the crack surface exert significant influence on the fatigue crack propagation behavior thereof. This influence strongly depends on the elastic moduli of the particles (Ep). As Ep is less than that of aluminium alloy (EAl), the particle accelerates the fatigue-crack-growth rate (FCGR) in the alloys due to the lubrication of the particles on the mating fracture surfaces. When the difference between Ep and EAl is small, the particle effect on the FCGRs of the alloys is small due to the counteraction between the decrease in friction and the promotion on the crack closure of mating fracture surfaces. When Ep is greater than EAl, the particles slow down the FCGRs of the alloys on account of significant crack closure effect. As Ep is much greater than EAl, the particles increase the FCGRs because of the increasing stress concentration at the crack tip.
2
Dostęp do pełnego tekstu na zewnętrznej witrynie WWW
The effects of service environment and pre-deformation on the fatigue behaviour of 2524 alloy were investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and fatigue tests. The results indicate that the fatigue crack-growth rate (FCGR) of the alloy in an aqueous environment increases with temperature ranging from 0 to 90 °C. At the same stress intensity factor range (ΔK), the FCGR of the alloy in an argon environment is the smallest, followed by that in air, and a 3.5% NaCl fog environment, while that in an exfoliation corrosion (EXCO) solution is the largest. A pre-deformation of 2% can significantly enhance the fatigue crack propagation resistance of this alloy in argon, air, and 3.5% NaCl fog environments, while 5% pre-deformation weakens the fatigue crack propagation resistance of the alloy accordingly. The pre-deformation effect on the FCGR of alloy in the EXCO solution environment is limited.
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.