Recrystallization and Microstructural Evolution During Hot Extrusion of Mg97Y2Zn1 Alloy
Recrystallization and Microstructural Evolution During Hot Extrusion of Mg97Y2Zn1 Alloy
复制标题
Mg97Y2Zn1合金热挤压过程中的再结晶及显微组织演变
DOI：
10.1007/s12540-014-3012-7
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发表时间：
2014-05-01
影响因子：
3.5
通讯作者：
Lin, Dongliang
中科院分区：
文献类型：
--
作者：
Chen, Bin;Li, Xiaoling;Lin, Dongliang
研究表明，挤压温度对Mg97Y2Zn1合金的显微组织和力学性能有很大影响。随着挤压温度从623 K增加到773 K，平均晶粒尺寸从3 m增加到8 m。动态再结晶（DRX）和静态再结晶（SRX），分别发生在变形过程中和变形后，观察。在相对较高的温度下挤压的合金表现出较低的强度，因为应变强化被源自DRX的软化所平衡。在623 K下获得的挤压组织中观察到3种类型的形貌，即大的再结晶晶粒、细的再结晶晶粒和未再结晶晶粒。完全再结晶晶粒中位错密度较高。在773 K下获得的挤压显微组织由尺寸更均匀的大晶粒组成。其再结晶程度较高，位错密度也有所下降。晶粒中的所有位错都被认为是位错。773 K挤压后，亚微米级析出相沿着新形成的再结晶晶界分布，对再结晶晶粒的长大有显著的钉扎作用。沉淀物可分为两种主要类型：混合型和单一型。
This study revealed that the extrusion temperature has a great influence on microstructure and mechanical properties of the Mg97Y2Zn1 alloy. The average grain sizes increased from 3 m to 8 m with increasing extrusion temperatures from 623 K to 773 K. Both dynamic recrystallization (DRX) and static recrystallization (SRX), which occur during and after deformation, respectively, were observed. The alloy, which extruded at a relatively high temperature, exhibited lower strength because the strain strengthening was balanced by the softening that originated from DRX. Three types of morphologies, namely, big recrystallized grains, fine recrystallized grains, and non-recrystallized grains, were observed in the extruded microstructures obtained at 623 K. The dislocation density was quite high in the fully recrystallized grain. The extruded microstructures obtained at 773 K were composed of large grains with more uniform size. Their degree of recrystallization was higher and the dislocation density also declined. All dislocation in the grain were distinguished as dislocations. Submicron scale precipitates were distributed along the newly formed recrystallized grain boundaries and had a remarkable pinning effect on the recrystallized grain growth after extrusion at 773 K. The precipitates can be divided into two main types: mixed type and single type.