Fatigue of Microlithographically-Patterned Free-Standing Aluminum Thin Film Under Axial Stresses

Abstract

Fatigue life as a function of number of stress cycles has been determined for three-layer titanium-aluminum-titanium thin-film specimens. For nominal stresses ranging from 50 to 90 percent of the upper-bound ultimate strength, the fatigue lives ranged up to 76 cycles. In all specimens, active cracks were observed after only a few stress cycles. These cracks grew with repeated cycling. The fatigue life was reached when the specimen could no longer sustain the maximum cyclic stress.