(南京理工大學(xué) 材料科學(xué)與工程系，南京 210094)
摘 要: 對AZ91D鎂合金進(jìn)行了室溫單軸應(yīng)力控制下的循環(huán)實(shí)驗(yàn)，研究幅值應(yīng)力σp、平均應(yīng)力σm及峰值應(yīng)力σa、應(yīng)力比及加載歷史對AZ91D鎂合金棘輪行為的影響。結(jié)果表明：棘輪應(yīng)變率隨σa和σm的提高而增大；σp和應(yīng)力比對棘輪行為產(chǎn)生很大的影響；先前高平均應(yīng)力、幅值應(yīng)力水平的循環(huán)歷史很大程度上抑制后續(xù)低應(yīng)力水平時(shí)的棘輪行為；先前低應(yīng)力水平對后續(xù)的棘輪行為也會(huì)產(chǎn)生影響；AZ91D鎂合金的εr與σp并不一一對應(yīng)，給出了εr與σm和σa的關(guān)系式。
關(guān)鍵字: AZ91D鎂合金；棘輪行為；應(yīng)力控制；單軸加載；本構(gòu)模型
uniaxial cyclic stressing
（Department of Material Science and Engineering, Nanjing University of Science and Technology,
Nanjing 210094, China）
Abstract: A number of uniaxial stress-controlled cycle loading experiments were conducted for AZ91D magnesium alloy at room temperature. The effects of the stress amplitude, mean stress, peak stress, stress ratio and loading history on the ratcheting behavior of AZ91D magnesium alloy were investigated. The results show that the ratcheting strain rate increases with increasing peak stress and mean stress. A prior cycling with higher mean stress or stress amplitude greatly decreases the ratcheting rate of the subsequent cycling with lower mean stress or stress amplitude. And prior cycling with lower stress has effect on the ratcheting behavior of the subsequent cycling with higher stress level. The correspondence between εr and σp is not one-to-one, the relationships among εr, σm and σa were obtained.
Key words: AZ91D magnesium alloy; ratcheting behavior; stress control; uniaxial loading; constitutive model
