The symmetrical push-pull fatigue tests in load control were carried out for prestrained polycrystalline Cu.The change in mechanical behaviour during cycling was recorded in detail and the effect of various degree of ...The symmetrical push-pull fatigue tests in load control were carried out for prestrained polycrystalline Cu.The change in mechanical behaviour during cycling was recorded in detail and the effect of various degree of prestraining on saturated behavior and dislocation structure was compared.The results show that the cyclic saturation state is still history-dependent at low stress amplitude and the dislocation structure after fatigue exhibits an “inheritance” be- havior.The level of softening was calculated at various load amplitudes and a softening threshold of about 0.43 to 0.45 of the flow stress was obtained.This is the same as that of low carbon steel.Three stages of cyclic processes and their mechanism have been described.展开更多
采用固相法制备了Ca Cu3Ti4O12多晶块体,研究了其介电常数随温度和频率的变化。结果表明,在温度为300 K、频率为1 k Hz时,多晶块的介电常数高达14 000;频率为1 k Hz时,介电常数基本不随温度的变化而改变。动态变化的极化弛豫使Ca Cu3Ti4...采用固相法制备了Ca Cu3Ti4O12多晶块体,研究了其介电常数随温度和频率的变化。结果表明,在温度为300 K、频率为1 k Hz时,多晶块的介电常数高达14 000;频率为1 k Hz时,介电常数基本不随温度的变化而改变。动态变化的极化弛豫使Ca Cu3Ti4O12多晶块具有巨介电常数,混合价Ti离子导致极化子的热激活使Ca Cu3Ti4O12多晶块的介电特性出现反常效应。展开更多
文摘The symmetrical push-pull fatigue tests in load control were carried out for prestrained polycrystalline Cu.The change in mechanical behaviour during cycling was recorded in detail and the effect of various degree of prestraining on saturated behavior and dislocation structure was compared.The results show that the cyclic saturation state is still history-dependent at low stress amplitude and the dislocation structure after fatigue exhibits an “inheritance” be- havior.The level of softening was calculated at various load amplitudes and a softening threshold of about 0.43 to 0.45 of the flow stress was obtained.This is the same as that of low carbon steel.Three stages of cyclic processes and their mechanism have been described.
文摘采用固相法制备了Ca Cu3Ti4O12多晶块体,研究了其介电常数随温度和频率的变化。结果表明,在温度为300 K、频率为1 k Hz时,多晶块的介电常数高达14 000;频率为1 k Hz时,介电常数基本不随温度的变化而改变。动态变化的极化弛豫使Ca Cu3Ti4O12多晶块具有巨介电常数,混合价Ti离子导致极化子的热激活使Ca Cu3Ti4O12多晶块的介电特性出现反常效应。
