Deformation behavior, microstructure evolution and hot workability of Mg-3.7Gd-2.9Y-0.7Zn-0.7Zr alloy
Deformation behavior, microstructure evolution and hot workability of Mg-3.7Gd-2.9Y-0.7Zn-0.7Zr alloy
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DOI：
10.1007/s12540-017-6352-2
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发表时间：
2017-05-01
影响因子：
3.5
通讯作者：
Zhang, Qi
中科院分区：
文献类型：
--
作者：
Jin, Xueze;Xu, Wenchen;Zhang, Qi
采用Gleeble-1500 D热模拟试验机，在温度375-475 A ℃，应变速率0.001 ~ 1 s（-1）范围内，对Mg-3.7Gd-2.9Y-0.7Zn-0.7Zr镁合金的热压缩变形行为进行了研究。结果表明，稀土元素的加入、LPSO相的引入以及Zr元素在晶界附近的偏聚是该镁合金具有较高激活能（Q = 354.08 kJ/mol）的主要原因。长周期堆垛有序相不仅能强化合金，促进动态再结晶形核，而且能在再结晶晶粒中再析出。基于MDMM和Murty失稳判据的加工图比基于DMM和Prasad失稳判据的加工图更精确。加工图显示出具有充分动态再结晶的两个可行区域：415-435 A ℃，0.001-0.006 s（-1）和435-475 A ℃，0.01-1 s（-1）。在低温和高应变速率条件下，易发生流动失稳，并出现流动局部化带和裂纹。
The deformation behavior of Mg-3.7Gd-2.9Y-0.7Zn-0.7Zr magnesium alloy has been investigated by thermal compression test conducted on a Gleeble-1500D thermal simulator in the temperature range of 375-475 A degrees C and strain rate range of 0.001-1 s(-1). It indicates that the addition of RE, the introduction of LPSO phases and the segregation of Zr element near the grain boundaries contributed to the high activate energy (Q = 354.08 kJ/mol) of the present Mg alloy. The long period stacking ordered (LPSO) phase could not only strengthen the alloy and contribute to the nucleation of dynamic recrystallization, but also re-precipitate in the recrystallization grains. The processing map based on MDMM and Murty's instability criterion was more precise than the one based on DMM and Prasad's instability criterion. The processing map exhibited two workable regions with sufficient dynamic recrystallization: 415-435 A degrees C, 0.001-0.006 s(-1) and 435-475 A degrees C, 0.01-1 s(-1). The flow instability was prone to occur at low temperature and high strain rate associated with the appearance of bands of flow localization and cracking.