Alloying behavior and deformation twinning in a CoNiFeCrAl0.6Ti0.4 high entropy alloy processed by spark plasma sintering

作者：Fu Zhiqiang^*; Chen Weiping; Fang Sicong; Zhang Dayue; Xiao Huaqiang; Zhu Dezhi

来源：Journal of Alloys and Compounds, 2013, 553: 316-323.

DOI：10.1016/j.jallcom.2012.11.146

• High entropy alloys
• Deformation twinning
• Mechanical alloying
• Spark plasma sintering

Inequi-atomic CoNiFeCrAl0.6Ti0.4 high 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 CoNiFeCrAl0.6Ti0.4 alloy 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, 2.52 GPa, 11.5% and 573 H-V, respectively. The fracture mechanism of CoNiFeCrAl0.6Ti0.4 high entropy alloy is mainly performed at intergranular fracture and plastic fracture mode.

• 出版日期2013-3-15
• 单位华南理工大学