Structural and Thermal Study of Nanocrystalline Fe-Al-B Alloy Prepared by Mechanical Alloying

Abstract

Nanostructured iron-aluminum alloy of Fe-25 at. pct Al composition doped with 0.2 at. pct B was prepared by mechanical alloying. The phase transformations and structural changes occurring in the studied material during mechanical alloying and during subsequent heating were investigated by SEM, XRD, and DSC techniques. The patterns so obtained were analyzed using the Rietveld program. The alloyed powders were disordered Fe(Al) solid solutions and Fe 2 B boride phase. The Fe 2 B boride phase is formed after 4 hours of milling. The crystallite size reduction to the nanometer scale (5 to 8 nm) is accompanied by an increase in lattice strains. The powder milled for 40 hours was annealed at temperatures of 523 K, 823 K, 883 K, and 973 K (250°C, 550°C, 610°C, and 700°C) for 2 hours. Low temperatures annealing are responsible for the relaxation of the disordered structure, while high temperatures annealing enabled supersaturated Fe(Al) solid solutions to precipitate out fines Fe 3 Al, Fe 2 Al 5 , and Fe 4 Al 13 intermetallics and, also the recrystallization and the grain growth phenomena.

Study of the Microstructural, Thermal, and Magnetic Properties of High-Energy Ball-Milled Nanocrystalline Fe(Al)

“…The magnetic properties remain partially stable with the independence of the Fe(Al) solid solution content as determined by XRD analysis. The same effect has been found in previous works [19,26]. Thus the formation of the Fe(Al) phase does not drastically affect magnetic behavior, and the main influence will be related to the Fe atoms' local environment and to Fe-Fe interatomic distance.…”

“…In addition, good refinement of the XRD patterns identifies the presence of bcc-Fe 3 Al intermetallic (Im-3m; a = 2.87977(1) Å). The same phase has been detected in previous work [26]. The formation of iron oxide is associated with the oxygen that is adsorbed at the powder surface particles when exposed to air after heating.…”

The effect of the amount of Y2O3 doped to the MA6000 alloy produced by mechanical alloying method on wear behavior

“…As the deformation continued, the flake-shaped powder particles hardened. In the later stages of MA, these powders' particles broke down and became smaller [15][16][17][18][19].…”