Calculation Research Of Phase Structure Stability And Elastic Properties For Mg-Al-Ce Alloy Metal Compound

Due to its unique advantages, Mg-Al allo ys have been widely used in aviat ion, aerospace, transportation and other industrial sectors. However, because of the existence o f the thermodynamic unstable phases, under the condit ions of more than 150 degrees, the strength and creep resistance o f Mg-Al allo ys can be reduced dramat ically. Therefore, it is a worthwhile research topic to improve the mechanical propert ies of magnesium allo ys by allo ying method. This article selected the Mg-Al allo y containing Ce as the research objects, and also apply the Castep and Dmo l program package based on densit y funct ional theory and experimental methods, calculated the occupat ion o f Ce in the Mg17Al12 phase and the phase structure stabilit y, elastic propert ies and electronic structure of Ce-Mg and Ce-Al intermetallic co mpounds. The study results are expected to provide theoret ical guidance for the development and applicat ion o f magnesium allo ys.The occupat ion o f rare earth Ce in the Mg17Al12 phase was calculated, and the result found that the calculat ion values o f the equilibrium constant o f crystal latt ice in this art icle and co mputat ional values in other papers are in good agreement with the experimental values wit hout Ce occupation, which showed that the calculat io n method used in this paper is reliable. It was concluded that the calculat ion results o f the equilibrium latt ice constants o f Ce occupied the latt ice o f Mg in Mg32Al24Ce2, Mg26Al24Ce8 and Mg10Al24Ce24 intermetallic compounds are also reliable. Besides, the calculat ion results o f the format ion and binding energy o f the allo y show that the Ce was difficult to occupy the latt ice of Mg or Al.The structural stabilit y and mechanical propert ies o f Mg, Al and Ce we re calculated, and the result found that the calculat ion values of the equilibrium constant of crystal lattice of Al3 Ce, Al Ce, Al2 Ce, Mg Ce, Mg3 Ce and Mg2 Ce intermetallic co mpounds in this art icle and computat ional values in other papers with the empirical datum basically tallies. The calculation results of the thermal calculat ion result s showed that the Mg Ce, Al2 Ce, Al3 Ce and Mg3 Ce intermetallic co mpounds can form a stable structure. Relat ive to other t ypes of structures, Al2 Ce and Al3 Ce have the strongest allo y forming abilit y. The binding energy calculat ion results show ed that t he stabilit y o f the structure is Al3 Ce, Al Ce, Al2 Ce, Mg Ce, Mg3 Ce and Mg2 Ce by descending order. The calculat ion results also found that the structural stabilit y of the system depends on the number o f electrons at the Fermi level.This co mputed results o f the elast ic constants of Al Ce, Mg Ce, Al2 Ce, Mg2 Ce, Al3 Ce, Mg3 Ce, Al Ce and Mg Ce intermetallic co mpounds in this paper are basically consistent with others calculat ion datum. According to the calculat ion of bulk modulus and shear modulus rat io(B/G), found that Mg3 Ce, Al2 Ce and Al3 Ce are britt le phase, Mg Ce, Mg2 Ce and Al Ce are duct ile phase. Among them, Al Ce has the best duct ilit y, and second is Mg2 Ce. Fro m the Young’s modulus(E) and Po isson’s rat io(V) co mputed values, the paper found, Mg2 Ce has the best plast ic, while the Mg3 Ce is the worst in Mg-Ce intermetallic co mpounds. Beside, Al Ce has the best plast icit y, while Al2 Ce is the worst in Al-Ce intermetallic co mpounds.