S.H. Ai
,
Y.Q. Wu
,
Z.G. Wang and Y.Zhang(State Key Laboratory for Fatigue and Fracture of Materials
,
Institute of Metal Research
,
The Chinese Academy of Sciences
,
Shenyang 110015
,
China)
金属学报(英文版)
Low cycle fatigue (LCF)tests under different total strain amplitudes have been conducted in order to ascertain the effect of precipitate sizes on LCF behavior of 8090 Al-Li alloy. A constant strain rate of 3×10-3s-1 and symmetrical triangular waveform were employed for all tests. It is found that the cyclic stress response of the alloy varied with the precipitate sizes and strain amplitudes. The materials in all conditions cyclically handen at first and the higher the strain amplitude, the greater the amount of hardening. The low cyclic flow stress is the highest in the peakaged condition. TEM and SEM observations demonstrated that cyclic stress-strain behavior and fracture mode of Al-Li alloy are closely related to an increase in the dislocation density and interaction between the precipitates and dislocations, sizes of δ particles and pricipitate free zone (PFZ) at grain boundaries.
关键词:
Al-Li alloy
,
null
,
null
