摘要
为了研究Al含量对FeCoCrNi合金组织性能的影响,采用多路送粉激光熔覆设备高通量制备Al_(x)CoCrFeNi高熵合金(0≤x≤0.9),通过X射线衍射仪、金相显微镜、扫描电子显微镜、电子探针和显微硬度计测试合金的相组成、显微组织结构、成分和硬度。结果表明:随着Al含量的增加,Al_(x)CoCrFeNi高熵合金由单一FCC相(x≤0.35)转变为FCC+BCC双相结构(0.35<x<0.85),最后转变为单一BCC结构(x≥0.85)。高熵合金的微观组织为柱状枝晶和均匀的等轴枝晶,Al含量增至x=0.5时,枝晶间开始出现明暗交替的调幅分解结构,由无序相A2和有序相B2组成。显微硬度测试结果表明:Al_(x)CoCrFeNi高熵合金的硬度基本随Al含量增加而增加,Al_(0.9)CoCrFeNi的硬度相较于FeCoNiCr提升了146%。此外,当Al含量达到一定值时(x≥0.6),合金中开始有裂纹出现,裂纹尺寸和密度随Al含量继续增加而增加,这主要与合金凝固区间变宽、在凝固温度附近的黏度值增加导致的热裂纹增加,以及由于脆性的BCC相和σ相含量增加引起的冷裂纹有关。
In order to study the effect of Al content on the microstructure properties of FeCoCrNi alloy,Al_(x)CoCrFeNi high-entropy alloy(0≤x≤0.9)was prepared by multi-channel laser cladding.The phase composition,microstructure,chemical composition and hardness of the alloy were test by X-ray diffractometry,metallography microscope,scanning electron microscope,electron probe and microhardness tester.The results show that with the increase of Al content,Al_(x)CoCrFeNi high-entropy alloy changes from single FCC phase(x≤0.35)to FCC+BCC biphase structure(0.35<x<0.85),and finally to BCC structure(x≥0.85).The microstructure of the high entropy alloy consists of epitaxial columnar dendrites and uniform equiaxed dendrites.When Al content reaches to x=0.5,characteristic structure of spinodal decomposition with alternating light and dark contrast starts to appear between the dendrites,which consists of disordered phase A2 and ordered phase B2.The microhardness test results show that the microhardness of Al_(x)CoCrFeNi alloys almost increases with the increasing Al content and a total of 146%improvement has been achieved when the Al content increases from x=0 to x=0.9.It should be noted that cracks begin to appear in the alloy when the Al content increases to a certain value(x≥0.6).The size and density of cracks increase with the increase of Al content.There are two main reasons.Firstly,the hot�cracking increases since the solidification range widen and their viscosity values near the solidification temperatures increase with the increasing Al content.Besides,cold cracking also increases as the brittle BCC andσphases increase with the increasing Al content.
作者
于丽莹
王晨
朱礼龙
张华
黄海亮
阮晶晶
张尚洲
江亮
周鑫
YU Liying;WANG Chen;ZHU Lilong;ZHANG Hua;HUANG Hailiang;RUAN Jingjing;ZHANG Shangzhou;JIANG Liang;ZHOU Xin(Institute for Advanced Studies in Precision Materials,Yantai University,Yantai 264005,Shandong,China;State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China)
出处
《材料工程》
EI
CAS
CSCD
北大核心
2024年第1期220-230,共11页
Journal of Materials Engineering
基金
泰山学者工程专项经费资助(tsqn202306162,tsqn202211115)
山东省高等学校青年创新团队发展计划(2022KJ272)。
作者简介
通讯作者:周鑫(1988—),男,教授,博士,研究方向为激光熔覆、热障涂层、材料基因工程,联系地址:山东省烟台市莱山区清泉路30号烟台大学(264005),E-mail:zhouxin@ytu.edu.cn。
