Alloying behavior and deformation twinning in a CoNiFeCrAl0.6Ti0.4 high entropy alloy processed by spark plasma sintering
Alloying behavior and deformation twinning in a CoNiFeCrAl0.6Ti0.4 high entropy alloy processed by spark plasma sintering
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DOI：
10.1016/j.jallcom.2012.11.146
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发表时间：
2013-03
影响因子：
6.2
通讯作者：
Z. Fu;Weiping Chen;Sicong Fang;Dayue Zhang;Huaqiang Xiao;Dezhi Zhu
中科院分区：
文献类型：
--
作者：
Z. Fu;Weiping Chen;Sicong Fang;Dayue Zhang;Huaqiang Xiao;Dezhi Zhu
采用机械合金化（MA）和放电等离子烧结（SPS）技术制备了CoNiFeCrAl0.6Ti0.4高熵合金。采用X射线衍射（XRD）、扫描电镜（SEM）、透射电镜（TEM）和Instron力学性能测试系统研究了CoNiFeCrAl0. 6Ti0. 4合金的合金化行为、显微组织、相演变和力学性能。在MA过程中，形成了由FCC相和亚稳BCC相组成的过饱和固溶体。SPS处理后，观察到两个FCC相（FCC 1和FCC 2）和一个新的BCC相。在SPS过程中，亚稳BCC相转变为FCC 2相和新的BCC相。同时，FCC 1相是MA过程中形成的初始FCC相。SPS处理后，纳米孪晶仅在部分FCC 1相中出现。在MA或SPS过程中可能发生形变孪晶。烧结态合金的相对密度高达98.83%，具有优异的综合力学性能。该合金的屈服应力、压缩强度、压缩比和维氏硬度分别为2.08、2.52GPa、11.5%和573HV。CoNiFeCrAl 0.6Ti 0.4高熵合金的断裂机制主要为沿晶断裂和塑性断裂。
Inequi-atomic CoNiFeCrAl0.6Ti0.4high entropy alloy has been designed and fabricated by mechanical alloying (MA) and spark plasma sintering (SPS). Alloying behavior, microstructure, phase evolution and mechanical properties of CoNiFeCrAl0.6Ti0.4alloy were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscope (TEM), as well as by an Instron testing system. During MA, a supersaturated solid solution consisting of a FCC phase and a metastable BCC phase was formed. Two FCC phases (named FCC1 and FCC2) and a new BCC phase were observed after SPS. During SPS, the metastable BCC phase transformed into the FCC2 phase and the new BCC phase. Meanwhile, the FCC1 phase was the initial FCC phase which was formed during MA. Moreover, nanoscale twins obviously presented only in partial FCC1 phase after SPS. Deformation twinning may be occurred during MA or SPS. The sintered alloy with a high relative density of 98.83% exhibits excellent comprehensive mechanical properties. The yield stress, compressive strength, compression ratio and Vickers hardness of the alloy are 2.08, 2.52GPa, 11.5% and 573 HV, respectively. The fracture mechanism of CoNiFeCrAl0.6Ti0.4high entropy alloy is mainly performed at intergranular fracture and plastic fracture mode.