关键词: 棘轮行为, 时间相关, 单轴循环, LY12CZ铝合金

Abstract:

A series of experiments were carried out to observe the cyclic deformation behaviors of LY12CZ aluminium alloy and its time-dependences at room and high temperatures. The main attention was paid to the effects of ambient temperature, stress level, loading waveform and peak stress hold on the ratchetting. It is shown that the LY12CZ aluminium alloy presents cyclic hardening feature and the extent of cyclic hardening depends on the strain amplitude. The ratchetting behavior of the material depends not only on the current stress amplitude and mean stress, but also on the loading histories. Although the LY12CZ aluminium alloy is not sensitive to the variation of strain rate in monotonic tension, its ratchetting behavior presents remarkable time-dependence: i.e., the ratchetting strain produced in the cyclic stressing with peak stress hold is larger than that without any hold and increases with the hold-time, and the ratchetting strain produced with sinusoidal waveform is apparently larger than that with the triangular one.

Key words: ratchetting , behavior,  , time dependence,  , uniaxial , cycling,  , LY12CZ , aluminium , alloy