Si对Inconel 718合金中γ相影响的第一性原理研究  

First-principles study of influence of Si on g phase in Inconel 718 alloy

作　　者：刘郅澄 周杰 陈凡[1] 彭彪 彭文屹[1] 章爱生[1] 邓晓华[2] 罗显芝 刘日新 刘德武 黄雨 阎军 Liu Zhi-Cheng;Zhou Jie;Chen Fan;Peng Biao;Peng Wen-Yi;Zhang Ai-Sheng;Deng Xiao-Hua;Luo Xian-Zhi;Liu Ri-Xin;Liu De-Wu;Huang Yu;Yan Jun(School of Physics and Materials,Nanchang University,Nanchang 330031,China;Institute of Space Science and Technology,Nanchang University,Nanchang 330031,China;Dexing Copper Mine of Jiangxi Copper Co.,Ltd.,Dexing 334200,China;Jiangxi Depu Mining Equipment Co.,Ltd.,Shangrao 334699,China)

机构地区：[1]南昌大学物理与材料学院,南昌330031 [2]南昌大学空间科学与技术研究院,南昌330031 [3]江西铜业股份有限公司德兴铜矿,德兴334200 [4]江西德普矿山设备有限公司,上饶334699

出　　处：《物理学报》2023年第18期338-345,共8页Acta Physica Sinica

基　　金：江西省重点研发项目(批准号:20212BBE53043);江西省大学生创新创业项目(批准号:S202110403003);江西省研究生创新项目(批准号:YC2022-s155)资助的课题。

摘　　要：随着航空航天、能源化工等领域的快速发展,人们对高温合金的性能提出了更高的期望.Inconel 718(简称IN 718)是目前用量最大的镍基高温合金,目前国内外关于Si对IN 718合金组织与性能影响的研究,尤其是在微观尺度上的研究,还存在大量空白.本文从第一性原理计算出发研究了Si掺杂对IN 718合金中γ相的影响,计算了Si掺杂前后γ相的晶格常数、总能量、缺陷形成能、形成热、结合能、态密度和差分电荷密度,并进行了布居分析.同时利用等离子熔覆的方法制备了IN 718涂层以及Si质量分数为2%的IN 718涂层,并对其进行显微组织及相结构的分析.计算结果表明,Si的掺杂改变了体系内原子的交互作用,影响了原子之间的价电子数量、电荷密度分布及原子之间键合的强度,从而扩大了γ相的晶胞体积,同时降低了γ相的稳定性.实验结果表明,Si掺杂会使得IN 718合金涂层组织发生由柱状晶向等轴晶的转变,并降低IN 718合金中γ相的体积分数,同时,Si掺杂会加剧合金组织内Nb和Cr元素的偏析.Inconel 718(IN 718)is the most widely used nickel-based high-temperature alloy today.It is widely adopted in important fields such as aerospace,energy and chemicals,and is also one of the few high-temperature alloys,of which some can be fabricated by using additive manufacturing.There is a lack of research on the effect of Si on the structure and properties of IN 718 alloy on a microscopic scale.In this paper,the effect of Si doping on the g phase in IN 718 alloy is investigated by first-principles calculations through using the CASTEP package.The lattice constants,total energy,defect formation energy,formation enthalpy,cohesive energy,density of states,and electron density difference of the g phase are calculated before and after Si doping,and population analysis is performed.The calculation of the lattice constant reveals that the doping of Si atoms expands the cell volume of the g phase supercell,which contributes to a certain solution strengthening effect,and is conducive to the improvement of the hardness of the alloy.The energy and electronic structure calculations show that the Si atoms prefer to occupy the Ni atomic positions in the g phase.The number of valence electrons between the atoms,the distribution of the charge density,and the strength of the bonds between the atoms also change with Si doping,thus modifying the interaction of the atoms within the g phase,reducing the stability of the g phase,and favouring the precipitation of the second phase.Besides,uniform and dense IN 718 coatings with low-coat Si doping are successfully fabricated by using plasma cladding.The experimental results demonstrate that Si doping has no significant effect on the type of matrix structure of IN 718 coatings,but causes a slight expansion of the lattice of the alloy,which is consistent with the calculation result.The addition of Si can result in a transformation of the alloy coating from columnar crystal to equiaxed crystal,refining the grain size of the alloy,while reducing the volume fraction of the g phase and increa

关 键 词：Inconel 718合金 第一性原理 Γ相 Si掺杂 

分 类 号：O469[理学—凝聚态物理]