Fatigue toughness of metals data compilation

Much of the fatigue data reported in the literature over the past 15 years which include both stress and strain measurements during cycling are complied. Over 1600 individual fatigue tests ranging in life from 1 to 107 reversals for 190 different materials and test conditions are reported. To aid future phenomenological analyses of fatigue, these data are presented in tabular form. About 1200 of these sets of data are complete enough to compute the total plastic strain hysteresis energy to failure (the fatigue toughness). It is found that the fatigue process involves or requires the dissipation of large amounts of total plastic strain hysteresis energy to failure. Virtually all of this energy is converted to heat which is dissipated to the surroundings. At lives of the order of one million reversals, one hundred times more plastic strain energy is required for fatigue failure than for monotonic fracture in tension. For most metals, this is sufficient energy to melt a sample ten times over. The fatigue toughness increases approximately as the 1/3 of the fatigue life for all metals. In general, the fatigue toughness is low for metals which are cast, have a low modulus of elasticity, are subjected to thermal strain cycling or are strain cycled about large tensile mean strains. With the exception of beryllium, the cast metals and thermal cycling data, about 80% of all of the data points fall within a one order of magnitude wide scatter band when the fatigue toughness is multiplied by the modulus ratio (Est/E) and plotted versus life. Total work to failure-life data from torsion, bending or impact fatigue tests on 44 additional metals (about 400 individual fatigue tests) are also included. These data cannot be reduced to a per unit volume basis because of the stress and strain gradients, but none-the-less exhibit the trend of increasing work to failure with increasing fatigue life. A brief review of the unifying relationships between stress range, plastic strain range, plastic strain hysteresis energy and fatigue life is given. A consistent set of simple fractional values are suggested for the various exponents which relate these quantities