The Development of the Structure, Morphology, and Fractional Composition of “Al−2B” Composite Powders in the Course of Mechanical Activation

Малкин, А. И.; Klyuev, V. A.; Ryazantseva, A. A.; Савенко, В. И.

doi:10.1134/s1061933x19060115

Cited by 4 publications

(4 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The boron-aluminium specific interface area was about 1.8 m 2 g À1 with an average volumetric size of the composite particles of 43 AE 2 mm. Detailed data on the structure and constitution of the composite powders are presented by Malkin et al (2019).…”

Section: Methodsmentioning

confidence: 99%

Formation and characterization of an Al-rich metastable phase in the Al–B phase diagram

et al. 2021

View full text Add to dashboard Cite

Vacuum heat treatment of mechanically alloyed powders of boron and aluminium leads to the formation of a metastable Al-rich phase, which can be quenched. Its structure, composition and thermal stability are established. With the chemical formula Al1.28B the rhombohedral phase is unusually rich in Al. The parameters of the unit cell determined from X-ray powder diffraction are a = 18.3464 (19), c = 8.9241 (9) Å, V = 2601.3 (6) Å3, space group R 3. It is stable on heating to 630°C. It is suggested that this phase is an important intermediate step in the formation of AlB2 and, eventually, of other borides; its nucleation and thermal stability are explained by high elastic energy hindering the formation of equilibrium phases at low temperatures.

show abstract

Section: Methodsmentioning

confidence: 99%

Formation and characterization of an Al-rich metastable phase in the Al–B phase diagram

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Investigation of the structure of composite AlB powders [33] showed that B was in an amorphous state, and the characteristic size of its crystallites in Al is 40–80 nm depending on the duration of mechanical processing. The contribution of defects in the Al matrix to the total enthalpy of the AlB composite did not exceed 0.35 kcal/mol [33], which is much less than the calculated enthalpy of formation of Al 1.28 B. We can therefore conclude that the main reason for the formation of this phase during the heat treatment of the composite AlB powders is the high‐energy amorphous state of B particles incorporated in the Al matrix.…”

Section: Resultsmentioning

confidence: 99%

“…On the other hand, the reason for the formation of the Al 1.28 B phase through the heat treatment of composite AlB powders obtained by mechanical alloying [12] can only be an increase in the enthalpy of the mechanically activated components of the AlB composites due to their highly defective structure compared to crystalline Al and B. Investigation of the structure of composite AlB powders [33] showed that B was in an amorphous state, and the characteristic size of its crystallites in Al is 40–80 nm depending on the duration of mechanical processing. The contribution of defects in the Al matrix to the total enthalpy of the AlB composite did not exceed 0.35 kcal/mol [33], which is much less than the calculated enthalpy of formation of Al 1.28 B.…”

Section: Resultsmentioning

confidence: 99%

“…Investigation of the structure of composite Al B powders [33] showed that B was in an amorphous state, and the characteristic size of its crystallites in Al is 40-80 nm depending on the duration of mechanical processing. The contribution of defects in the Al matrix to the total enthalpy of the Al B composite did not exceed 0.35 kcal/mol [33], which is much less than the…”

Section: T a B L E 1 The Calculated Formation Enthalpies And Bond Len...mentioning

confidence: 99%

See 1 more Smart Citation

Metastable aluminum boride: density functional theory study of prerequisites of formation

Flyagina,

Markov,

Malkin

et al. 2023

Int J of Quantum Chemistry

View full text Add to dashboard Cite

Aluminum borides have significant practical interest as energetic additives to fuels, explosives and propellants due to their favorable thermodynamic and kinetic characteristics. Density functional theory calculations with periodic boundary conditions have been performed to evaluate the enthalpy of formation of two aluminum borides: the well‐known aluminum diboride AlB2 and the metastable Al1.28B phase, which precedes the formation of AlB2 during heat treatment of mechanically activated composite aluminum‐boron powders, as well as aluminum ion‐implanted with boron. The calculated formation enthalpy of AlB2 is −3.6 kcal/mol, which agrees well with estimates from literature. The enthalpy of formation of Al1.28B, calculated for the first time, is 4.8 ± 0.4 kcal/mol. To understand the prerequisites for the formation of Al1.28B observed in experiments, the enthalpy of formation of supersaturated solid solutions of B in Al has been evaluated. The reasons for the preferential formation of the metastable Al1.28B phase over the thermodynamically stable AlB2 phase are discussed.

show abstract

Granulometry of Metal Micropowders Treated in a Planetary-Type Ball Mill

2022

View full text Add to dashboard Cite

The Development of the Structure, Morphology, and Fractional Composition of “Al−2B” Composite Powders in the Course of Mechanical Activation

Cited by 4 publications

References 5 publications

Formation and characterization of an Al-rich metastable phase in the Al–B phase diagram

Formation and characterization of an Al-rich metastable phase in the Al–B phase diagram

Metastable aluminum boride: density functional theory study of prerequisites of formation

Granulometry of Metal Micropowders Treated in a Planetary-Type Ball Mill

Contact Info

Product

Resources

About