Microstructural development during hot working of Mg-3Al-1Zn
Microstructural development during hot working of Mg-3Al-1Zn
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DOI：
10.1007/s11661-007-9207-5
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发表时间：
2007-08-01
影响因子：
2.8
通讯作者：
Barnett, M. R.
中科院分区：
文献类型：
--
作者：
Beer, A. G.;Barnett, M. R.
研究了镁合金AZ31在热压缩过程中变形态和铸态原始组织的演变规律。研究了应变、温度和应变速率对动态再结晶组织的影响。动态再结晶百分率和动态再结晶晶粒尺寸对初始组织和变形条件敏感。较低的Z条件（较低的应变速率和较高的温度）产生较大的动态再结晶晶粒尺寸和增加的DRX的百分比，如预期的。铸态材料的DRX百分比增加速率显著低于锻造材料。此外，在铸态样品中，随着Z的减小，DRX百分比不继续向完全DRX增加。这些观察结果可归因于变形在材料的DRX部分中变得局部化。此外，动态再结晶晶粒尺寸通常在铸态材料中比在锻造材料中大，这可能归因于与孪晶相关的动态再结晶和变形的不均匀性。铸态材料的取向图（来自电子背散射衍射（EBSD）数据）揭示了不连续动态再结晶（DDRX）和与双晶相关的动态再结晶作为主要机制的证据，以及连续动态再结晶（CDRX）和颗粒刺激成核（PSN）的一些表现。
The microstructural evolution is examined during the hot compression of magnesium alloy AZ31 for both wrought and as-cast initial microstructures. The influences of strain, temperature, and strain rate on the dynamically recrystallized microstructures are assessed. Both the percentage dynamic recrysallization (DRX) and the dynamically recrystallized grain size were found to be sensitive to the initial microstructure and the applied deformation conditions. Lower Z conditions (lower strain rates and higher temperatures) yield larger dynamically recrystallized grain sizes and increased percentages of DRX, as expected. The rate with which the percentage DRX increases for the as-cast material is considerably lower than for the wrought material. Also, in the as-cast samples, the percentage DRX does not continue to increase toward complete DRX with decreasing Z. These observations may be attributed to the deformation becoming localized in the DRX fraction of the material. Also, the dynamically recrystallized grain size is generally larger in as-cast material than in wrought material, which may be attributed to DRX related to twins and the inhomogeneity of deformation. Orientation maps of the as-cast material (from electron backscattering diffraction (EBSD) data) reveal evidence of discontinuous DRX (DDRX) and DRX related to twins as predominant mechanisms, with some manifestation of continuous DRX (CDRX) and particle-stimulated nucleation (PSN).