Volume 7, Issue 4 (April 2010)
Effects of Microstructure on the Incipient Fatigue and Fretting Crack Processes in Al-Cu-Li Alloys
The influence of microstructure on the crack nucleation and growth under fatigue and fretting loadings was investigated on two different Al-Cu-Li alloys used for aerospace applications (2050-T8 and 2196-T8) and containing different hardening precipitates (mainly T1 precipitates for 2050-T8 and T1+δ′ for 2196-T8). Fatigue tests have been carried out on specimens with a central hole to take into account the stress concentration present in riveted plates. The number of cycles for crack initiation in fatigue is found to be smaller in the plate which contains larger intermetallic particles. Concerning the fretting tests, cracking seems to be essentially controlled by contact conditions and no influence of precipitation microstructure was observed for the experimental conditions investigated.