Analysis of the Valence Electron Structures of the Strengthening Phases Al8Fe4Ce and Al4Ce in Al-Fe-Ce Alloy

2011 ◽  
Vol 194-196 ◽  
pp. 1291-1295 ◽  
Author(s):  
Hua Qu ◽  
Wei Dong Liu ◽  
Yu Ying Liu
Keyword(s):  
Network Structure ◽  
Valence Electron ◽  
Grain Refining ◽  
Electron Theory ◽  
The Third ◽  
Empirical Electron Theory ◽  
Atom Group ◽  
The Matrix ◽  
Bond Network ◽  
Strengthening Phases

Based on the empirical electron theory of solids and molecules (EET), the valence electron structures (VESs) of the strengthening phases Al8Fe4Ce and Al4Ce in Al-Fe-Ce alloy were calculated, then the relationships between the VESs and strengthening, stability of the alloy and grain refining were analyzed. The results show that the distribution of the bond network of Al8Fe4Ce is uniform, the third and the fourth bonds in the bond network of Al4Ce is the weakest segment of the whole bond network structure, and the strongest bond in the bond network of Al8Fe4Ce and Al4Ce is stronger than that of the matrix of the alloy. The VES of Al8Fe4Ce is favourable to stability of the alloy. During solidifying of the alloy, because the bonds formed by Ce atom and its adjacent atoms are all strong, that hinders Al atoms adjacent to Ce atom to involve in the growth of other grains and at the same time hinders the growth of the Ce atom group, so the structure of the alloy can be refined.

ANALYSIS OF VALENCE ELECTRON STRUCTURE ONFe3AlCxPRECIPITATED FROM C-ALLOYED IRON ALUMINIDES

2013 ◽  
Vol 20 (01) ◽  
pp. 1350005 ◽  
Author(s):  
XIAO-FENG TIAN ◽  
WEI-KE ZHANG ◽  
YU QI
Keyword(s):  
Valence Electron ◽  
Theoretical Explanation ◽  
Electron Structure ◽  
Iron Aluminides ◽  
Electron Theory ◽  
Valence Electron Structure ◽  
Alloyed Iron ◽  
Empirical Electron Theory ◽  
The Matrix ◽  
Brittle Phase

Carbides of Fe3AlCxprecipitated from iron aluminides can strengthen the matrix; the empirical electron theory (EET) was applied to analyze the attribute of carbides in the paper, giving theoretical explanation on the matrix and precipitation. Valence electron structure (VES) of Fe3AlCxwas studied in detail, comparison with the iron aluminides matrix, the hard and brittle phase of Fe3AlCxcan be interpreted form the viewpoint of valence electron structure.

Study on the Stability and Phase Transition of Precipitated Phases Al6Fe and Al3Fe in Al-Fe Alloy

2011 ◽  
Vol 306-307 ◽  
pp. 438-442
Author(s):  
Hua Qu ◽  
Wei Dong Liu
Keyword(s):  
Phase Transition ◽  
Valence Electron ◽  
Electron Theory ◽  
Electron Pairs ◽  
Empirical Electron Theory ◽  
Equilibrium Solidification ◽  
The Stability ◽  
State Group ◽  
Precipitated Phases ◽  
Strengthening Phases

Based on the empirical electron theory of solids and molecules theory(EET), the valence electron structures(VESs) of the strengthening phases Al3Fe and Al6Fe in Al-Fe alloy are calculated, then the stability of Al3Fe and Al6Fe, the precipitated sequence under the non-equilibrium solidification, the phase transition during aging and the effects of alloy elements are discussed. The results show that the values of covalent electron pairs on the strongest bondn1, the total forming bond abilityF, and the number of atom state groupσNof Al3Fe and Al6Fe are bigger than that of Mg17Al12 and Mg2Si, so the stability of Al3Fe and Al6Fe is better. The total forming bond ability of Al6Fe is far smaller than that of Al3Fe, so Al6Fe generates first under the equilibrium solidification. The strongest bond of Al6Fe is weaker than that of Al3Fe, so Al6Fe is easy to be broken up and form the more stable Al3Fe finally during aging. The addition of alloy elements changes the VES of Al6Fe and makes its values ofF,σNandn1increased, the stability of Al6Fe is strengthened too, which delays the Al6Fe→Al3Fe transition and improves the transition temperature.

Theoretical Calculation of the Polytypism Transition Temperature of Titanium Alloys on the Valence Electron Level

2012 ◽  
Vol 152-154 ◽  
pp. 342-347
Author(s):  
Hua Qu ◽  
Wei Dong Liu
Keyword(s):  
Transition Temperature ◽  
Titanium Alloys ◽  
Valence Electron ◽  
Pure Titanium ◽  
Electron Theory ◽  
Electron Level ◽  
Valence Electron Structure ◽  
Electron Pairs ◽  
Stable Element ◽  
Empirical Electron Theory

Based on the polytypism transition temperature(PPT) of pure titanium, the the empirical electron theory of solids and molecules(EET) and the basic theory of the phase transformation of titanium alloys, a new method to calculate the PTT of titanium alloys is put forward after calculating the valence electron structure(VES) parameter nA which is the covalence electron pairs on the strongest bond of alloy phases, the crystal cell weight of  and  phases in the structure, the compensation coefficient of the phase and the temperature coefficient of  stable element. After calculating the PTT of some common titanium alloys, we find that the theoretical values are consistent with the experimental ones, so it is feasible to calculate the polytypism transition temperature of the titanium alloys on the covalence electron level.

Relationships between the Abilities of the Forming Bond of the Precipitated Phases and their Precipitations and Phases Transition in Al-Fe-Si Alloy

2010 ◽  
Vol 152-153 ◽  
pp. 1049-1053
Author(s):  
Hua Qu ◽  
Wei Dong Liu ◽  
Chuang Liu ◽  
Gang Zhou ◽  
Xiao Lu Shen
Keyword(s):  
High Temperature ◽  
Solid Solutions ◽  
Electron Theory ◽  
Empirical Electron Theory ◽  
The Matrix ◽  
Cooling Speed ◽  
The Stability ◽  
Precipitated Phases

According to the empirical electron theory of solid and molecule, the valence election structures of the matrix  of Al-Fe-Si alloy, solid solutions of -Al-Fe and -Al-Fe-Si, precipitated phases of A13(Fe,Si), Al8Fe2Si and Al12Fe3Si and their abilities of the forming bond were calculated, then the relationships between the abilities of the forming bond of the main precipitated phases in Al-Fe-Si alloys and their precipitations and phases transition were studied in this paper. From the results we find that the ability of the forming bond of Al12Fe3Si (637.23) is small, that of Al3(Fe,Si) (670.52) is large and that of Al8Fe2Si (1038.27) is the largest; the larger the cooling speed, the more amount of the precipitated first of Al12Fe3Si, the few amount of the precipitated of Al3(Fe,Si) and Al8Fe2Si; the stability of Al12Fe3Si is smaller than that of Al3(Fe,Si) and Al8Fe2Si, and under high temperature, the phase of Al12Fe3Si can grow up and coarsen and even change into Al3(Fe,Si) and Al8Fe2Si.

Analysis of Structural Condition and Thermodynamics Condition of Graphite Heterogeneity Nucleation in Cast Iron

2011 ◽  
Vol 299-300 ◽  
pp. 576-579
Author(s):  
Hua Qu ◽  
Wei Dong Liu
Keyword(s):  
Crystal Structure ◽  
Cast Iron ◽  
Valence Electron ◽  
Large Angle ◽  
Structural Condition ◽  
Nucleation Theory ◽  
Electron Theory ◽  
Modern Times ◽  
Bond Forming ◽  
Empirical Electron Theory

Based on the empirical electron theory of solid and molecule, the valence electron structures(VESs) of graphite, CaS and MnS in cast iron are calculated, their bond-forming energy F of the structure unit and bond-forming energyEof the crystal plane are defined and calculated. Combined with the nucleation theory of the liquid metal,Fand E are applied to analyze the thermodynamics condition of graphite heterogeneity nucleation in undercooling liquid of case iron, i.e.,GL-FG>GL-FH,>. According to the coincidence lattice model of large-angle grain boundary used commonly in modern times, the corresponding structural condition is analyzed, i.e., the crystal structure of graphite should have the better lattice contract ratio with the crystal structure of its annexed heterogeneous particles.

The Valence Electron Structure of High-Entropy Alloys

2017 ◽  
Vol 1142 ◽  
pp. 3-7
Author(s):  
Bo Cheng ◽  
Yun Kai Li ◽  
Gui Qin Hou
Keyword(s):  
Valence Electron ◽  
Electron Pair ◽  
Electron Structure ◽  
High Entropy Alloys ◽  
Electron Theory ◽  
Valence Electron Structure ◽  
High Entropy ◽  
Melting Temperatures ◽  
Empirical Electron Theory ◽  
Pair Number

Empirical Electron Theory in Solids and Molecules (EET) was used to analyze the valence electron structure of ZrTiHfVNb, ZrTiHfVTa and ZrTiHfNbMo high-entropy alloys. The parameters characterizing the valence electron structure of high-entropy alloys were calculated, which were used to discuss the hardness and melting temperature of high-entropy alloys. The results show that the hardness of high-entropy alloys is positively correlated to the shared electron pair number in valence electron structure. The theoretical melting temperatures of high-entropy alloys were predicted by the parameters characterizing the valence electron structure.

Effects of Mo(Ni) on Valence Electron Structures of TiC/Fe Cermets

2008 ◽  
Vol 368-372 ◽  
pp. 1119-1122 ◽  
Author(s):  
Zheng Guang Zou ◽  
Yi Wu ◽  
Fei Long ◽  
Wen Wu Xu ◽  
Dong Ye Yao
Keyword(s):  
Binding Energy ◽  
Electron Density ◽  
Valence Electron ◽  
Electron Cloud ◽  
Metal Phase ◽  
Structure Model ◽  
Electron Theory ◽  
Ceramic Phase ◽  
Empirical Electron Theory

Based on the empirical electron theory (EET) of solids and molecules, the valence electron structures (VESs) of TiC-Mo(Ni)-Fe system were calculated by building proper structure model. The results indicate that additives of Mo and Ni improve the interface conjunction factors of the cermets in different ways. By adding Mo, the VESs of the ceramic phase are improved for the formation of the rim phase (Ti1-xMox)C, which leads to the enhancement of the interface conjunction, while the improvement of the VESs on metal phase by adding Ni is due to the formation of the Fe100-yNiy. Mo and Ni additives increase the interface electron density of cermets, that is, the adding of the Mo and Ni enhance the overlapping grade of the electron cloud on interface and increase the binding energy of the interface, which is propitious to the wettability. The best wettability was found at x=0.5 or y=30.

Application on Statistical Value of Phase Structure Formation Factor to Fe-C Phase Diagram

2011 ◽  
Vol 299-300 ◽  
pp. 246-249
Author(s):  
Wei Hua Xue ◽  
Xin Ren ◽  
Zhi Yu Gao ◽  
Hai Fang Shi
Keyword(s):  
Phase Diagram ◽  
Structure Formation ◽  
Phase Structure ◽  
Valence Electron ◽  
Calculation Methods ◽  
Formation Factor ◽  
Electron Theory ◽  
Valence Electron Structure ◽  
Austenitic Phase ◽  
Empirical Electron Theory

Based on the empirical electron theory in solids and molecules (EET), the statistical value of phase structure formation factor (S') was calculated by using the calculation methods of statistical value of alloying valence electron structure parameters. The effects of alloying elements upon austenitic zone of Fe-C phase diagram were discussed. The results show that: 1) Mn and Ni can increase the S' value of γ-Fe and austenitic phase, which increase their stability, leading to expand the γ-zone; 2) Cr, Mo and Si can increase the S' value of ferrite and cementite, which make them easier to precipitate, leading to reduce γ-zone. The research results agree well with real situations.

Relationship between Valence Electron Structures and Mechanical Properties of ZL203

2012 ◽  
Vol 152-154 ◽  
pp. 336-341
Author(s):  
Hua Qu ◽  
Wei Dong Liu
Keyword(s):  
Mechanical Properties ◽  
Valence Electron ◽  
Strengthening Effect ◽  
Strengthening Phase ◽  
Electron Theory ◽  
Valence Electron Structure ◽  
Empirical Electron Theory ◽  
Dislocation Movement ◽  
Aging Stage ◽  
The Relationship

Based on the empirical electron theory of solids and molecules(EET) and valence electron theory of composition design of alloy, the valence electron structure(VES) of phases and phase interfaces of ZL203 are calculated in this paper, and the relationship between the VESs and mechanical properties are also studied. The results are as followed: 1) The of GP is bigger than of a, in other words, the resistance of dislocation movement in GP zone is bigger than that of in a matrix. 2) Compared with a matrix, the phases of q¢¢、q¢、q all have strengthening effects. From the bond combination of atoms composed in the strengthening phase of view, the strengthening effect of q is the best, that of q¢ is second, that of q¢¢ is the worst. 3) The precipitation sequence determined bynAis well accordance with that of depended on thermodynamics free energy. 4) The electron density difference Dr of a/GP, a/q" and a/q¢ interfaces increases one by one, and the stress of these interfaces also increases one by one, therefore the strength falls down one by one. 5) Combined with FSFs and ICFs, we can deduce that the best aging stage of ZL203 is the end of the precipitation of q¢¢ and the beginning of the precipitation of q¢.

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