Al-matrix composite based on Al-Ca-Ni-La system additionally reinforced by L12 type nanoparticles  

L12型纳米颗粒增强以Al-Ca-Ni-La体系为基体的铝基复合材料

作　　者：Torgom K.AKOPYAN Nikolay A.BELOV Evgeniya A.NAUMOVA Nikolay V.LETYAGIN Tat'yana A.SVIRIDOVA 

机构地区：[1]National University of Science and Technology MISiS,4 Leninsky pr.,Moscow 119049,Russia

出　　处：《Transactions of Nonferrous Metals Society of China》2020年第4期850-862,共13页中国有色金属学报（英文版）

基　　金：financial support of the grant of the Russian Science Foundation(Project No.18-79-00345)(preparation of alloys,electron microscopy(SEM,EMPA,TEM),tensile tests);Ministry of Science and Higher Education of the Russian Federation in the framework of Increase Competitiveness Program of MISiS(No.P02-2017-2-10)(thermodynamic calculations,dilatometry,DSC and XRD).

摘　　要：The structure of the quaternary Al?(2?4)wt.%Ca?Ni?La system near the aluminum corner has been studied using computational analysis in the Thermo-Calc program and experimental studies(electron microscopy,microprobe analysis and X-ray diffraction).Based on the phase equilibria data obtained,the experimental projection of the liquidus surface and solid state phase-field distribution of the Al?Ca?Ni?La system have been proposed.Microstructure studies reveal that the alloys with the 2?4 wt.%Ca,2?4 wt.%Ni and 1?3 wt.%La ranges have an ultra-fine hypoeutectic structure with 30%volume fraction of eutectic intermetallics,which allows one to classify these alloys as natural Al-matrix composites.The ultra-fine eutectic structure produces significant strengthening,the magnitude of which can be well described using the modified Orowan looping mechanism model.Small additives of Zr and Sc(0.2 and 0.1 wt.%,respectively)lead to significant strengthening(by^25%)due to the formation of L12 type phase(Al3(Zr,Sc))nanoparticles during annealing of the alloy at 350?400℃.Due to the high volume fraction of eutectic intermetallics,the new alloys have low coefficients of thermal expansion and high thermal stability of the structure and mechanical properties.结合Thermo-Calc热模拟程序计算和实验(电子显微镜、微探针分析和X射线衍射)研究四元系Al-(24)Ca-Ni-La(质量分数,%)合金在铝角附近的结构。根据得到的相平衡数据,提出Al-Ca-Ni-La体系液相面和固相相场分布的实验投影。显微组织研究表明,含2%4%Ca、2%4%Ni和1%3%La(质量分数)的合金具有超细的亚共晶组织,共晶金属间化合物的体积分数为30%,因此,可以将这些合金归类为天然Al基复合材料。超细共晶结构产生显著的强化作用,其机制可以很好地用修订的Orowan循环模型描述。在350400℃退火过程中,由于L12型相(Al3(Zr,Sc))纳米颗粒的形成,添加少量的Zr和Sc(分别为0.2%和0.1%,质量分数)具有显著的强化作用(提高约25%)。由于共晶金属间化合物的体积分数高,该新合金具有低的热膨胀系数、高的结构热稳定性和力学性能。

关 键 词：Al-Ca alloys EUTECTIC INTERMETALLICS phase diagram rare earth element NANOCOMPOSITE microstructure mechanical properties 

分 类 号：TB33[一般工业技术—材料科学与工程]