Ti_(x)(Fe_(15)Co_(35)Ni_(35)Cr_(15))_(100-x)高熵合金的微结构与力学性能

Microstructure and Mechanical Properties of Ti_(x)(Fe_(15)Co_(35)Ni_(35)Cr_(15))_(100-x) High Entropy Alloys

高熵合金以其优异的力学和物化性能,被誉为下一代重点发展的合金材料。文中通过真空电弧炉熔制合金,利用OM、XRD、SEM、EDS、显微硬度计和万能试验机等分析测试,研究分析了Ti_(x)(Fe_(15)Co_(35)Ni_(35)Cr_(15))_(100-x)(x=0,2,4,6,8,10,12,14)多主元合金的微观结构和力学性能。结果表明:在宽泛的钛含量范围内,合金的基体相始终保持单一的FCC结构,凝固形态以树枝晶为特征。随着Ti含量增加,晶间η相析出数量增多,合金的相组成由单相FCC固溶体向FCC固溶体加少量晶间η-(Ni,Co)_(3)Ti的复相结构过渡,固溶体形态则由细小的等轴晶向粗大的树枝晶转变,相应地合金的显微硬度和屈服强度趋于升高,而塑韧性下降。合金性能值域较宽,显微硬度为HV197~510,屈服强度为171~1065 MPa。其中Ti_(10)Ni_(32)Co_(32)Fe_(13)Cr_(13)高熵合金的塑性应变大于50%,显微硬度达HV483,屈强服度达到870 MPa,是综合性能优异的高强度高熵合金材料。

High entropy alloy is considered as the next generation of key development alloy materials due to its excellent mechanical and physicochemical properties.In this study,the microstructure and mechanical properties of Ti_(x)(Fe_(15)Co_(35)Ni_(35)Cr_(15))_(100-x) multi-component alloy were characterized by OM,XRD,SEM,EDS,microhardness tester and universal testing machine.The results show that in a wide range of Ti content,the matrix phase of the alloy always keeps a single FCC structure,and the phase morphology features dendrite.With increasing Ti content,the amount of intergranularηphase precipitation increases;the phase constituent of the alloy changes from single FCC solid solution to FCC solid solution with a small amount of intergranularη-(Ni,CO)_(3)Ti.The morphology of solid solution transforms from fine equiaxed crystal to coarse dendrite.Accordingly,the micro-hardness and yield strength of the alloy tend to increase,while the toughness decreases.The alloy has a wide range of properties,the micro-hardness is HV 197-510 and the yield strength is 171-1065 MPa.Ti_(10)Ni_(32)Co_(32)Fe_(13)Cr_(13) high entropy alloy has more than 50%plastic strain,HV 483 micro-hardness and 870 MPa yield strength.It is a high-strength high-entropy alloy with excellent comprehensive properties.