循环加载频率对镁合金棘轮应变的影响  

Effects of cyclic loading frequency on ratcheting of magnesium alloy

作　　者：师雨晴 段国升 宋令慧 武保林 杜兴蒿 Yuqing SHI;Guosheng DUAN;Linghui SONG;Baolin WU;Xinghao DU(School of Safety Engineering,Shenyang Aerospace University,Shenyang 110136,China;Shandong Key Laboratory for High Strength Lightweight Metallic Materials,Institute of New Materials at Qilu University of Technology(Shandong Academy of Sciences),Jinan 250014,China;School of Materials Science and Engineering,Shenyang Aerospace University,Shenyang 110136,China)

机构地区：[1]沈阳航空航天大学安全工程学院,沈阳110136 [2]齐鲁工业大学(山东省科学院)新材料研究所山东省轻质高强金属材料重点实验室,济南250014 [3]沈阳航空航天大学材料科学与工程学院,沈阳110136

出　　处：《航空学报》2024年第24期267-280,共14页Acta Aeronautica et Astronautica Sinica

基　　金：国家自然科学基金(51901140);齐鲁工业大学人才科研项目(2023RCKY014)。

摘　　要：在不同加载速率下镁合金的机械性能存在差异,为探讨循环频率与棘轮应变的关系,对挤压态AZ31B镁合金进行应力控制下的循环实验,研究频率对镁合金的棘轮应变及其演化过程的影响。分别讨论了频率为1.0、2.0、5.0 Hz时镁合金的循环变形过程,结果表明:挤压态AZ31B镁合金在循环变形过程中存在明显的棘轮效应,且在相同平均应力作用下棘轮应变与频率的关系并不是单调的,频率为5.0 Hz时的棘轮应变处于1.0 Hz与2.0 Hz之间。这是由于频率为1.0 Hz与2.0 Hz时频率较低,在一个循环周期下应力作用的时间更长,因此1.0 Hz时形成的棘轮应变比2.0 Hz时的更大;而频率为5.0 Hz时,相对于1.0 Hz和2.0 Hz时孪生-去孪生机制所占比重更大,循环中具有更低的硬化率,故棘轮应变较2.0 Hz时更大。不同频率下,循环前期棘轮应变均快速增加,经一定循环次数后趋于稳定。There are differences in the mechanical properties of magnesium alloys at different loading rates,in order to explore the relationship between cyclic frequency and ratcheting strain,cyclic experiments under stress control were carried out on extruded AZ31B magnesium alloys to study the effect of frequency on the ratcheting strain of magnesium alloys and its evolution process.The cyclic deformation process of magnesium alloys at frequencies of 1.0,2.0,5.0 Hz are discussed respectively.The results show that there is an obvious ratcheting effect during cyclic deformation of extruded AZ31B magnesium alloys,and the relationship between the ratcheting strain and frequency under the same average stress is not monotonic.The results also show that value of the ratcheting strain at 5.0 Hz is in the range between 1.0 Hz and 2.0 Hz,which is due to the fact that when the frequency is 1.0 Hz versus 2.0 Hz,the stresses act for a longer period of time under a cyclic cycle at a lower frequency,so the value of the ratcheting strain formed at 1.0 Hz is greater than at 2.0 Hz.However,at a frequency of 5.0 Hz,the twinning-de-twinning mechanism is more predominant relative to 1.0 Hz and 2.0 Hz,and there is a lower hardening rate in the cycle,so the ratcheting strain values are greater than at 2.0 Hz.At different frequencies,the ratcheting strain increases rapidly in the pre-cycle period and stabilizes after a certain number of cycles.

关 键 词：频率 棘轮行为 疲劳 应力控制 孪生机制 

分 类 号：V252.2[一般工业技术—材料科学与工程]