EXPERIMENTAL AND NUMERICAL FATIGUE ANALYSIS OF A PRECIPITATION HARDENED HIGH COPPER ALLOY WITH DIFFERENT NOTCH FACTORS

A new generation of high performance copper alloys is drawing the attention of electronic industry. Electronic devices are increasingly subject to rough service conditions that could not be afford by pure copper, which have always been used because of its good electric conductivity and its reasonable cost. Nowadays, a good electric conductivity must be accompanied by mechanical strength and relaxation resistance, in order to meet electronic industry that requires always better performing materials, increasingly subjected to high loads, vibrations and high temperatures. A precipitation hardened high copper alloy is a material that responses to all these needs. Here, the room temperature fatigue behavior of a precipitation hardened high copper alloy is examined. Sub-sized and normal-sized specimens are manufactured from two sheets of different high copper alloys in four different geometries corresponding to different notch factors in order to investigate size effects on the fatigue strength. Load controlled fatigue tests have been carried out and the number of cycles to failure is then obtained in order to derive the SN-curves of the materials. The maximum likelihood method is used to analyze the data, so that also censored data like run-out can be taken into account. Finally, the results are discussed and the conclusions drawn.