Flow stress and microstructural evolution of the horizontal continuous casting Al-0.96Mn-0.38Si-0.18Fe alloy during hot compression
Flow stress and microstructural evolution of the horizontal continuous casting Al-0.96Mn-0.38Si-0.18Fe alloy during hot compression
复制标题
DOI：
10.1016/j.msea.2013.01.075
复制
发表时间：
2013-06
期刊：
影响因子：
6.4
通讯作者：
Hui Zhang;Fulin Jiang;X. Shang;Luoxing Li
中科院分区：
文献类型：
--
作者：
Hui Zhang;Fulin Jiang;X. Shang;Luoxing Li
在Gleeble-1500热模拟试验机上对水平连铸Al-0.96Mn-0.38Si-0.18Fe合金进行了温度为350°C ~ 500°C、应变速率为0.01s-1 ~ 10 s-1的热压缩试验，并利用光学金相和透射电镜观察了热压缩过程中的组织变化。结果表明，在低于450°C和较高应变速率下的流动应力随着应变的增加而增加，并且在峰值之后趋于恒定，显示出稳态流动直到高应变。当温度高于450°C且应变速率较低时，流变应力达到一个平台，然后略有下降，显示出流变软化。峰值应力水平随变形温度的升高和应变速率的降低而降低，可用双曲正弦方程中的Zener-Hollomon参数表示，热变形激活能为159.24kJ/mol。动态回复导致稳态流动，而流动软化与动态再结晶和析出相的动态转变有关。所设计的柱状粗晶粒能够在高于450°C和较低的应变速率下进行GDRX。
Hot compression tests of the horizontal continuous casting Al–0.96Mn–0.38Si–0.18Fe alloy were preformed on Gleeble-1500 system in the temperature range from 350°C to 500°C and at strain rate range from 0.01s−1to 10s−1, and the associated microstructural changes were studied by the observations of optical metallographic and transmission electron microscope. The results show that the flow stress below 450°C and at higher strain rates increases with increasing strain and tends to be constant after a peak value, showing a steady state flow until high strains. While above 450°C and at lower strain rates, the flow stress reaches a plateau and then decline slightly, showing a flow softening. The peak stress level decreases with increasing deformation temperature and decreasing strain rate, which can be represented by a Zener–Hollomon parameter in the hyperbolic-sine equation with the hot deformation activation energy of 159.24kJ/mol. The steady state flow results from dynamic recovery whereas flow softening is associated with dynamic recrystallization and dynamic transformation of precipitates. The designed columnar coarse grains were capable of GDRX above 450°C and at lower strain rates.