An Investigation of the Fatigue Behavior of Tantalum Including the Effect of Strain Aging PDF Download

Author: D. Y. Wang
Publisher:
ISBN:
Category : Tantalum
Languages : en
Pages : 27

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Book Description
A study has been made of the fatigue of commercially pure polycrystalline tantalum under axial loading with zero mean stress. A wrought stress-relieved tantalum material and two recrystallized materials, each having different interstitial impurity element contents, were tested at room temperature; also a recrystallized material was tested at an elevated temperature in an argon gas environment. In addition, surface metallographic observations of the mode of surface crack initiation were made. Tests of specimens representing all three conditions indicated the existence of a definite fatigue limit, similar to that of medium to low strength steel. The variation of the fatigue limit and the knee position is influenced by the test temperature and may be predicted by temperature-dependent mobility of the interstitial atom in diffusion. The experimental results appear to confirm the previously proposed theory that the fatigue limit of a body-centered-cubic metal is attributable to the manifestion of strain aging occurring during alternating stressing. An analysis was made to show the effect of strain aging on ftigue as a function of the test temperature and interstitial content, taking into consideration the experimental observations and the present theories of the mechanism of fatigue.