Enhanced mechanical properties of Al-4.5 wt.% Cu single crystals with seaweed morphology
Enhanced mechanical properties of Al-4.5 wt.% Cu single crystals with seaweed morphology
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DOI：
10.1016/j.jmrt.2022.02.011
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发表时间：
2022-02
期刊：
影响因子：
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通讯作者：
Yumin Wang;Yarong Yang;Liang Qiao;Z. Liu;Hui-juan Xing;Shuangming Li
中科院分区：
文献类型：
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作者：
Yumin Wang;Yarong Yang;Liang Qiao;Z. Liu;Hui-juan Xing;Shuangming Li
虽然海藻图案是最重要的一类界面形态，但它们的机械性能还没有得到很好的理解。在这里，我们通过控制Al-4.5wt.%的定向凝固过程中依赖于取向的界面能各向异性来产生轴向海藻（AS）、倾斜海藻（TS）和退化海藻（DS铜合金。电子背散射衍射（EBSD）的无序形态的表征表明，海藻生长的<110>方向，这是显着不同的<100>规则枝晶。在室温下，使用拉伸试验机评估海藻形态试样的机械性能。海藻形态试样的极限拉伸强度（σB）、延伸率（δf）和韧性分别达到：AS为186.1 MPa、45.5%和72.9 MJ m−3; TS为151.6 MPa、50.9%和67.9 MJ m−3; DS为164.3 MPa、62.2%和89.4 MJ m−3。相对于具有规则枝晶的试样，DS试样的伸长率和韧性分别为109%和96%，表现出显着的改善。此外，海藻形态的试样显示出更强的加工硬化效应（AS，TS和DS试样，分别为n= 0.33，0.30和0.38）比枝晶试样（n= 0.22）。海藻形态标本的连续尖端分裂产生了细化和均匀分布的第二相颗粒，这有助于上述增强。我们的研究结果提供了潜在的洞察力的海藻形态标本的机械性能，一个主题的铝合金设计至关重要。
While the seaweed pattern is one the most important classes of interfacial morphologies, their mechanical properties are not well understood. Here we produce axial seaweed (AS), tilted seaweed (TS) and degenerate seaweed (DS) by controlling the orientation-dependent interfacial energy anisotropy during the directional solidification of an Al-4.5 wt.% Cu alloy. Characterization of the disordered morphology by electron backscattered diffraction (EBSD) showed that the seaweed growth was oriented in the <110> direction, which was significantly different from that of a <100> regular dendrite. The mechanical properties of seaweed morphology specimens were evaluated using a tensile-testing machine at room temperature. The ultimate tensile strength (σb), elongation (δf) and toughness of the seaweed morphology specimens reach 186.1 MPa, 45.5% and 72.9 MJ m−3, respectively, for AS; 151.6 MPa, 50.9% and 67.9 MJ m−3, respectively, for TS; and 164.3 MPa, 62.2% and 89.4 MJ m−3, respectively, for DS. With respect to specimens with regular dendrite, the DS specimen exhibited a significant improvement in the elongation and toughness of 109% and 96%, respectively. Additionally, the seaweed morphology specimens show a stronger work hardening effect (n= 0.33, 0.30 and 0.38 for AS, TS and DS specimens, respectively) than the dendrite specimen (n= 0.22). Continuous tip-splitting of the seaweed morphology specimen produced refined and uniformly distributed second-phase particles that contributed to the aforementioned enhancement. Our results provide the underlying insight of the mechanical properties of seaweed morphology specimens, a topic crucial to the design of aluminum alloys.