Influence of Compressive Pre-strain on Tensile Fatigue in Two Types of Aluminum Alloys

Excerpt

The effect of pre-strain on fatigue behavior in various kinds of materials has been reported on several times thus far (Ref 1-11). That being said, however, the number of actual systematic research works on this topic is quite few, and it is still unclear whether pre-straining is of any benefit in fatigue properties, presumably depending on the material and its microstructure. Furthermore, in particular, the effect of compressive pre-strain on pulsative (tensile) fatigue behavior has not been reported on in correlation with cyclic plastic strain response for the materials strengthened by different mechanisms, which is very important in engineering application. However, it has so far been considered that the measurement of cyclic plastic strain response under the condition of tensile fatigue is extremely difficult because of its smallness. In the present study, the influence of compressive pre-strain on fatigue properties in two types of aluminum alloys (5056-H34 Al alloy and 6061-T6 Al alloy) has been investigated. 5056-H34 Al is the alloy strengthened mainly by solid solution, while 6061-T6 is the precipitation-strengthened alloy (H34: work-hardened and stabilized, T6: solid-solution treated and artificially aged). …