Published online by Cambridge University Press: 28 July 2016
The term “fatigue” is given to the progressive failure of a metal under the repeated application of a cycle of stress. Although investigators have been working for more than a hundred years to determine the mechanism by which fatigue failure occurs, the problem is still not fully understood. The simple slip theories of Ewing and Rosenhain in 1899, Ewing and Humphrey in 1903 and of Gough and his collaborators from 1923 to 1933 appear now to be only partially true, according to some of the modern theories. These suggest that other factors such as polygonisation, deformation bands and crystallite formations, all play an important part.