Nucleation and growth of L1_(2)-Al_(3)RE particles in aluminum alloys:A first-principles study  

作　　者：Touwen Fan Zixiong Ruan Feng Zhong Chaoyang Xie Xiaofeng Li Dongchu Chen Pingying Tang Yuanzhi Wu 

机构地区：[1]College of Science,Hunan Institute of Technology,Hengyang 421002,China [2]Research Institute of Automobile Parts Technology,Hunan Institute of Technology,Hengyang 421002,China [3]School of Materials Science and Engineering,North University of Chin1,Taiyuan 030051,China [4]School of Material Science and Hydrogen Energy Engineering,Foshan University,Foshan 528001,China [5]Key Laboratory of New Electric Functional Materials of Guangxi Colleges and Universities,Nanning Normal University,Nanning 530023,China

出　　处：《Journal of Rare Earths》2023年第7期1116-1126,I0005,共12页稀土学报（英文版）

基　　金：Project supported by the R&D plan for Key Areas in Guangdong Province (2020B010186001);the National Natural Science Foundation of China (52171115,52071299)。

摘　　要：The internal mechanisms of nucleation and growth of L1_(2)-AI_(3)RE(RE=Sc,Y,La-Lu) second phases in Al alloys were investigated by combining first-principles calculations with quasi-harmonic approximation(QHA).The calculated results show that the diffusion rate D_s and chemical potential AG_V increase with the increase of temperature.With the increase of atomic number,the D_s and the strain energy ΔE_(CS)increase firstly from Sc to La,and then decreases,while the calculated interface energy γ_(α/β) and ΔG_V show opposite tendency.Based on above calculated results,the critical nucleation radius R*and coarsening rate K_(LSW) are obtained from the classical nucleation theory(CNT) and LSW model of the Ostwald ripening of particles,respectively.With the increase of atomic number,the R*increases firstly,and then decreases for all planes at finite temperatures.Whereas the K_(LSW) shows opposite variation to the R^(*).From this point of view,it is reasonably speculated that Y and later RE elements can replace the expensive Sc for heat-resistance Al alloys.The solubility c_(∞) of particles is usually very small at low temperature,and there is obvious solubility only when the temperature reaches 600 K.The surface energies E_(sur) of AI_(3)RE compounds and Al solid solution are respectively larger and smaller than that of pure Al,respectively,except for the surface(001) and(110) of Al_(3)La.For all planes,with the increase of atomic number of RE,E_(sur) decreases firstly from Sc to La,and then increases linearly to Lu.These results are helpful for designing high performance heat-resistance Al alloys.

关 键 词：First-principles calculations Diffusion rate Quasi-harmonic approximation Particle nucleation and growth Rare earths 

分 类 号：TG146.21[一般工业技术—材料科学与工程]