Grain-size effect on the deformation of Mg-3Al-3Sn alloy: Experiments and elastic-viscoplastic self-consistent modeling
Grain-size effect on the deformation of Mg-3Al-3Sn alloy: Experiments and elastic-viscoplastic self-consistent modeling
复制标题
晶粒尺寸对 Mg-3Al-3Sn 合金变形的影响：实验和弹粘塑性自洽模型
DOI：
10.1016/j.ijplas.2021.103018
复制
发表时间：
2021
影响因子：
9.8
通讯作者：
Zeng Xiaoqin
中科院分区：
文献类型：
--
作者：
Zhu Gaoming;Wang Leyun;Sun Yingjun;Shang Xiaoqing;Wang Jie;Wang Huamiao;Zeng Xiaoqin
晶粒细化可以显著改变镁合金的拉伸行为。其潜在机制尚不清楚。在这里，我们报告了Mg-3Al-3Sn（wt.%，AT 33合金的屈服强度σ 0.2符合Hall-Petch定律，而应变硬化指数h降低。采用考虑晶粒尺寸的弹粘塑性自洽（EVPSC）模型，模拟了4种不同晶粒尺寸（10-97 μm）的AT 33轧制试样的拉伸应力-应变曲线和晶格应变演化。该模型成功的关键是它允许初始临界分辨剪切应力（CRSS）和不同滑移模式的位错成核系数是晶粒尺寸的函数。粗晶试样由于同时形成形变孪晶而具有较高的位错形核系数。该模型预测，棱柱形滑移是占主导地位的变形模式，在这AT 33合金，金字塔和滑移是更活跃的粗晶粒样品比细晶粒样品。
Grain refinement can significantly change the tensile behavior of Mg alloys. The underlying mechanisms are unclear yet. Here we report that grain refinement of a Mg–3Al–3Sn (wt.%, AT33) alloy increases the yield strength (σ 0.2) following the Hall-Petch law, while decreases the strain hardening exponent (h). Tensile stress-strain curves and lattice strain evolution of four rolled AT33 samples with different grains sizes (10–97 μm) can be simulated by an elastic-viscoplastic self-consistent (EVPSC) model that takes grain size into account. The key to the model's success is that it allows both the initial critical resolved shear stress (CRSS) and the dislocation nucleation coefficient of different slip modes to be functions of the grain size. The coarse-grained samples have higher dislocation nucleation coefficient due to concurrently formed deformation twins. The model predicts that prismatic slip is the dominant deformation mode in this AT33 alloy; pyramidal and slips are more active in coarse-grained samples than in fine-grained samples.