AlxFeCoNi2.05近共晶高熵合金组织和力学性能研究

(西安工业大学 材料与化工学院,西安710021

共晶高熵合金; 初生相; B2相; L12相; 显微组织; 力学性能

Research on Microstructure and Mechanical Properties of AlxFeCoNi2.05 Near-Eutectic High-Entropy Alloys
ZHANG Yangqing,YAO Yuhong,HOU Yongchang

(School of Materials and Chemical Engineering,Xi'an Technological University,Xi'an 710021,China)

eutectic high entropy alloys; primary phase; L12 phase; B2 phase; microstructure;

DOI: 10.16185/j.jxatu.edu.cn.2020.01.013 http://xb.xatu.edu.cn

备注

为研究Al元素含量对AlxFeCoNi2.05(x=0.85,0.95,1.05)近共晶高熵合金组织和拉伸性能的影响,通过扫描电子显微镜(SEM)观察合金的显微组织和断口形貌,采用X射线衍射仪(XRD)和透射电子显微镜(TEM)研究Al原子含量对晶体结构的影响。试验结果表明:在该共晶系高熵合金中,Al元素为共晶形成元素。当Al元素含量为0.95时,合金具有由层片状L12相和B2相组成的完全共晶组织,其中富含Fe和Co元素的L12相为领先相,B2相富含Ni和Al元素。当Al元素含量为0.85时,合金组织为L12初生+(L12+B2)共晶组成的亚共晶组织; 当Al元素含量为1.05时,合金组织为B2初生+(L12+B2)共晶组成的过共晶组织。正是由于显微组织的差异,AlxFeCoNi2.05(x=0.85,0.95,1.05)合金的屈服强度由650 MPa降低到450 MPa和510 MPa,而延伸率由12%大幅度增加到29%和27.5%。

The paper studies the effect of Al content on the microstructure and tensile properties of AlxFeCoNi2.05(x=0.85,0.95 and 1.05)near-eutectic high-entropy alloys,the microstructure and fracture morphology of the alloy were observed with a scanning electron microscopy(SEM),the crystal structure was analyzed with an X-ray diffractometer(XRD)and a transmission electron microscope(TEM).Results indicate that Al is an eutectic forming element in the AlFeCoNi2.05 near-eutectic high-entropy alloy.The AlFeCoNi2.05 alloy with 0.95 Al has a completely eutectic structure composed of the leading lamellar L12 phase rich in Fe and Co and B2 phase rich in Ni and Al.The alloys with 0.85 and 1.05 Al respectively has a hypoeutectic structure of primary L12 phase + eutectic(L12+B2)phase and a hypereutectic structure of primary B2 phase + eutectic(L12+B2)phase.Because of difference microstructure,the yield strengths of AlxFeCoNi2.05(x=0.85,0.95,1.05)alloys reduce from 650 MPa to 450 MPa and 510 MPa,while their elongation increases significantly increase from 12% to 29% and 27.5%.