摘要
采用真空电弧熔炼炉制备了Co_(36)Ni_((37-x))Cr_(20)Al_(3)Ti_(2)Nb_(x)(x=2、3和4,原子分数,%)中熵合金,利用扫描电镜(SEM)、能谱仪(EDS)、透射电镜(TEM)及拉伸试验机等研究了合金的微观组织、力学性能、强化机制及变形机制。结果表明:随着Nb含量的增加,合金晶粒的平均尺寸增大,且晶界处析出相的成分和形状也发生改变。当Nb含量为2%和3%时,析出相为富Al、Nb的片状析出相,当Nb含量提升至4%时,出现了富Ti、Nb的块状析出相。随Nb含量的增加,合金的强度提高,伸长率下降。Nb含量由2%提升到4%,合金的屈服强度由940 MPa提升至1177 MPa,极限抗拉强度由1246 MPa提升至1271 MPa,伸长率由13.67%下降至3.75%。合金强度提升的原因是Nb元素的加入增强了固溶强化和沉淀强化。合金形变初期主要依靠层错诱导形变实现,合金变形后期主要依靠位错运动实现。
Co_(36)Ni_((37-x))Cr_(20)Al_3Ti_(2)Nb_x(x=2,3 and 4,at%) medium-entropy alloys(MEAs) were prepared by a vacuum arc-melting furnace,and the microstructure,mechanical properties,strengthening mechanism and deformation mechanism of the alloys were studied using scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS) analysis,transmission electron microscopy(TEM) and tensile testing machine.The results show that with the increase of Nb content,the average size of the alloys grains increases,and the composition and shape of precipitates at grain boundaries also change.When the Nb content is 2% and 3%,the precipitates are sheet-like precipitates rich in Al and Nb.When the Nb content increases to 4%,block like precipitates rich in Ti and Nb appear.With the increase of Nb content,the strength of the alloy increases and the elongation decreases.The Nb content increases from 2% to 4%,the yield strength of the alloys increases from 940 MPa to 1177 MPa,the ultimate tensile strength increases from 1246 MPa to 1271 MPa,and the elongation decreases from 13.67% to 3.75%.The reason for the increase in the alloy strength is that the addition of Nb element enhances solid solution strengthening and precipitation strengthening.In the early stage of alloy deformation,it is mainly achieved by the stacking faults-induced deformation,while in the later stage of alloy deformation,it is mainly achieved by dislocation movement.
作者
娄照坤
刘继文
林雅婷
王君阳
张璐
LOU Zhao-kun;LIU Ji-wen;LIN Ya-ting;WANG Jun-yang;ZHANG Lu(School of Materials Science and Engineering,Shenyang Aerospace University,Shenyang 110136,China;Shenyang University of Aeronautics and Astronautics Key Laboratory for the Digitisation of Aerospace Manufacturing Processes for National Defence,Shenyang 110136,China)
出处
《材料热处理学报》
CAS
CSCD
北大核心
2024年第7期117-126,共10页
Transactions of Materials and Heat Treatment
基金
沈阳航空航天大学航空制造工艺数字化国防重点学科实验室开放基金资助项目(SHSYS202205)
沈阳航空航天大学创新创业训练计划项目(D202302271902448979)。
关键词
中熵合金
力学性能
强化机制
变形机制
medium-entropy alloy
mechanical property
strengthening mechanism
deformation mechanism
