摘要
为探讨非对称循环应力作用下镁合金的棘轮行为,对AZ31B挤压镁合金进行了室温下压-压应力控制的循环实验,研究了不同平均应力下AZ31B挤压镁合金棘轮应变及其演化过程,讨论了平均应力作用下循环变形过程的主导塑性变形机制及其对棘轮行为的影响。结果表明,AZ31B挤压镁合金在压-压循环过程中存在明显的棘轮现象,相比于位错滑移,孪生-去孪生机制对棘轮应变的形成起到关键作用,决定了棘轮应变的变化率。在平均应力为0、-45、-75、-135 MPa时,循环过程中形成的棘轮应变随平均压应力的增加而增加,经一定循环次数后趋于稳定,棘轮应变率随循环次数的增加先急剧下降后维持不变。
The uniaxial ratcheting behaviors of an extruded AZ31 B magnesium alloy was investigated with a series of compression-compression cyclic stress-controlled experiments at ambient temperature.Effects of different mean stresses on the ratcheting stress and its evolution were examined.The mechanism of dominant plastic deformation under mean stress and its effect on the ratcheting behavior in the process of cyclic deformation were discussed.Results show that remarkable ratcheting behavior occurs in the extruded AZ31 B magnesium alloy in the process of compression-compression cycles.Instead of the dislocation slip,the twinning-detwinning mechanism plays a key role in the formation of ratcheting strain and determines the rate of ratcheting strain.When the mean stress is 0,-45,-75,-135 MPa,the ratcheting strain formed in the cyclic process increases with the increase of the compressive mean stress,and tends to be stable after a certain number of cycles.The ratcheting strain rate decreases sharply with the increase of the number of cycles until it remains unchanged.
作者
韩重韬
宋令慧
段国升
武保林
HAN Chongtao;SONG Linghui;DUAN Guosheng;WU Baolin(School of Safety Engineering,Shenyang Aerospace University,Shenyang 110136,China;Key Laboratory for High Strength Lightweight Metallic Materials of Shandong Province,Advanced Materials Institute of Shandong Academy of Sciences,Qilu University of Technology(Shandong Academy of Sciences),Jinan 250014,China)
出处
《航空学报》
EI
CAS
CSCD
北大核心
2022年第12期568-578,共11页
Acta Aeronautica et Astronautica Sinica
基金
国家自然科学基金(51901140)
辽宁省自然科学基金(2019-ZD-0238)。
关键词
棘轮行为
应力控制
平均应力
变形机制
AZ31B
ratcheting behavior
stress-controlled
mean stress
deformation mechanism
AZ31B
