Microstructural development and room temperature tensile property of directionally solidified Ti-47Al alloy by electromagnetic confinement and directional solidification
Microstructural development and room temperature tensile property of directionally solidified Ti-47Al alloy by electromagnetic confinement and directional solidification
复制标题
电磁约束定向凝固定向凝固Ti-47Al合金的显微组织发展及室温拉伸性能
DOI：
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发表时间：
2018
影响因子：
2.7
通讯作者：
Jun Shen
中科院分区：
文献类型：
--
作者：
Yujun Du;Jun Shen
采用电磁约束定向凝固技术，在不同的生长速度下获得了直径为18 mm的Ti-47Al样品。在Ti-43Al-3Si晶种的控制下，在10μm/S的生长速度下，获得了平行的片层组织，当生长速度提高到25和50μm/S时，虽然在过渡初期片层组织仍然很好地排列，但由于新的β和α的形核和长大，导致片层取向失效，最终形成倾斜和垂直的片层组织。对不同片层组织的室温拉伸性能进行了测试，结果表明，所设计的片层组织具有693 Mpa的拉伸强度和10.0%的延伸率。这是迄今报道的二元γ-TiAl合金中的最大值，远远高于其他两种类型的片层组织。用扫描电子显微镜和透射电子显微镜观察了片层组织的断裂行为。用两种模型解释了不同层状结构的断裂机理。
Ti-47Al samples with a diameter of 18 mm are obtained by electromagnetic confinement and directional solidification at different growth velocities. Controlled by a Ti-43Al-3Si seed, the α grains are aligned well and the parallel lamellar microstructure is obtained at the growth velocity of 10 μm/s. With the growth velocity increases to 25 and 50 μm/s, although the lamellar microstructures are still aligned well in the initial transition stage, the lamellar alignment fails due to the nucleation and growth of new β and α grains and then the inclined and perpendicular lamellar microstructures form eventually. The room temperature tensile properties of the different lamellar microstructures are measured and the results show that the desired lamellar microstructure has a tensile strength of 693 MPa and an elongation of 10.0% simultaneously. They are the maximum values that have been reported in binary γ-TiAl alloys so far and are far higher than those of the other two types of lamellar microstructures. The fracture behaviors of the lamellar microstructures are checked by scanning electron microscopy and transmission electron microscopy. Two models are used to illustrate the fracture mechanism of the different lamellar structures.