定向凝固CoCrCuFeNiTi_(0.8)高熵合金的组织与力学性能  

Microstructure and mechanical properties of CoCrCuFeNiTi_(0.8) high-entropy alloy prepared by directional solidification

作　　者：徐义库[1] 李聪玲 黄兆皓 陈永楠[1] 朱丽霞 XU Yi-ku;LI Cong-ling;HUANG Zhao-hao;CHEN Yong-nan;ZHU Li-xia(School of Material Science and Engineering,Chang’an University,Xi’an 710064,China;CNPC Tubular Goods Research Institute,Xi’an 710077,China)

机构地区：[1]长安大学材料科学与工程学院,西安710064 [2]中国石油管材研究院,西安710077

出　　处：《中国有色金属学报》2021年第6期1494-1504,共11页The Chinese Journal of Nonferrous Metals

基　　金：中国留学基金委“青年骨干教师出国研修计划”项目(201906565024);中央高校基础研究基金资助项目(300102318205,310831161020,310831163401,300102319304);长安大学创新创业培训计划资助项目(202010710143);陕西省自然科学基金重点资助项目(2019JZ-27);陕西省自然科学基础研究项目(2019JLM-47)。

摘　　要：采用定向凝固技术制备CoCrCuFeNiTi_(0.8)高熵合金,研究不同抽拉速率(5μm/s、10μm/s、25μm/s)对合金微观组织及力学性能的影响。使用光学显微镜(OM)对其微观组织进行分析,并用X射线衍射仪(XRD)和透射电子显微镜(TEM)确定合金的相组成。结果表明:在所有的抽拉速率下,合金的微观组织均为树枝状,随着凝固过程的进行,枝晶取向趋于一致。当抽拉速率从5μm/s增加到25μm/s时,枝晶直径从469.70μm减小到355.48μm,枝晶组织明显细化,分形维数从1.5981增加到1.6158,枝晶生长更加规律,说明抽拉速率的增加使合金获得了细密的枝晶阵列。此外,在抽拉速率为25μm/s时,定向凝固CoCrCuFeNiTi_(0.8)高熵合金达到了最大压缩应变11.98%和最大抗压强度1440.19MPa,证明定向凝固技术能有效地改善CoCrCuFeNiTi_(0.8)高熵合金的力学性能。The CoCrCuFeNiTi_(0.8) high-entropy alloy was prepared by directional solidification technology.The effects of different withdrawal rates(5μm/s,10μm/s,25μm/s)on the microstructure and mechanical properties of the alloy were studied.The microstructures of the alloy were analyzed by optical microscope,and the phase composition of the alloy was determined by X-ray diffraction and transmission electron microscope.The results show that the microstructure of the alloy is dendritic at all withdrawal rates,the dendrite orientation tends to be uniform as the solidification process goes on.When the withdrawal rates increase from 5μm/s to 25μm/s,the dendrite diameter decrease from 469.70μm to 355.48μm,and the fractal dimension increases from 1.5981 to 1.6158.The dendrite structure is obviously refined with the increase of withdrawal rate to 25μm/s.Moreover,the maximum compressive strength reaches 1440.19 MPa and the maximum plastic strain is 11.98%,which prove that the directional solidification technology can effectively improve the mechanical properties of the CoCrCuFeNiTi_(0.8) high-entropy alloy.

关 键 词：高熵合金 定向凝固 一次枝晶间距 力学行为 

分 类 号：TF11.31[冶金工程—冶金物理化学]