摘要
为了获得兼具高强度与高延展性的Al-Co-Cr-Fe-Ni系高熵合金,采用电弧熔炼的方法成功制备了Al_(1.2)Co_(x)CrFeNi(x=1,1.6,2.2,2.8)高熵合金并对其微观组织和力学性能进行了系统研究。结果表明:在Al_(1.2)Co_(x)CrFeNi合金体系中,Co元素具有诱导BCC相向FCC相转变的能力,随着Co含量的原子比例从1增加至2.8,FCC相的体积分数从0%增加到59%,BCC相的体积分数从100%降低至41%。压缩实验的结果表明,Co元素的加入对于提高Al_(1.2)Co_(x)CrFeNi高熵合金的塑性有重要作用,但对高熵合金的强度无明显影响。随着Co含量的增加,Al_(1.2)Co_(x)CrFeNi高熵合金的断裂应变从16.9%增加到30%,极限抗压强度由2128 MPa降低至1913 MPa,其中最大抗压强度为2361 MPa,平均硬度由513.7HV降低至323.4HV。Co含量的增加促使了合金的原子半径差的降低,从而减弱了因Al元素的大原子半径引起的合金晶格畸变效应和固溶强化效应,同时Co含量的增加也提高了价电子浓度(VEC),以上两个参数的改变是合金中FCC相体积分数的增加的主要因素。FCC相体积分数的增加是该体系合金塑性提高的主要原因。
To obtain Al-Co-Cr-Fe-Ni high entropy alloys(HEAs)with high strength and high ductility,Al_(1.2)Co_(x)CrFeNi(x=1,1.6,2.2,2.8)HEAs were successfully prepared by arc melting method and its microstructure and mechanical properties were systematically studied.The results show that in Al_(1.2)Co_(x)CrFeNi alloy,Co element can induce the transformation from BCC to FCC phase.With the increase of the atomic ratio of Co from 1 to 2.8,the volume fraction of FCC phase increases from 0%to 59%,and the volume fraction of BCC phase decreases from 100% to 41%.The results of compression experiment show that the addition of Co plays an important role in improving the plasticity of Al_(1.2)Co_(x)CrFeNi high entropy alloys but has no obvious effect on the strength of the high entropy alloys.With the increase of Co content,the fracture strain of Al_(1.2)Co_(x)CrFeNi HEAs increases from 16.9%to 30%.The ultimate compressive strength decreases from 2128 MPa to 1913 MPa,and the maximum compressive strength is 2361 MPa,and the average hardness decreases from 513.7HV to 323.4HV.The increase of Co content decreases the atomic size difference of the alloys,which weakens the lattice distortion effect and solid solution strengthening effect caused by the large atomic radius of Al element.At the same time,the increase of Co content also increases the valence electron concentration(VEC)of the alloys.The changes of the above two parameters are the main factors for the increase of FCC phase volume fraction in the alloy.The increase of the volume fraction of FCC phase is the main reason for the improvement of the plasticity of the alloy.
作者
赵森林
陈希章
ZHAO Senlin;CHEN Xizhang(College of Mechanical and Electrical Engineering,Wenzhou University,Wenzhou 325035,Zhejiang,China)
出处
《材料工程》
EI
CAS
CSCD
北大核心
2023年第5期104-111,共8页
Journal of Materials Engineering
基金
国家自然科学基金项目(51975419)
浙江省重点研发计划(2021C04022)。
关键词
高熵合金
相变
微观组织
力学性能
原子半径差
价电子浓度
high entropy alloy
phase transition
microstructure
mechanical property
atomic size difference
valence electron concentration
