Nanocrystalline Al–Fe intermetallics – light weight alloys with high hardness

Nanocrystalline or amorphous matrix Al60Fe15Ti15(Co/Mg/Zr)5–5%B composites produced by consolidation of mechanically alloyed powders – lightweight materials with high hardness

“…To fulfil this, applying a high pressure and limiting the high temperature exposure time during consolidation should be considered. It is shown in the literature that applying the high pressure hot-pressing technology allows to retain the nanocrystalline or amorphous structure of powders during consolidation [18e20, 22,23], and we have demonstrated that application of a high pressure influences grain growth at elevated temperature by hindering it [19,20,22].…”

“…The composites hardness was 6.29 GPa (amorph-matrix) and 6.94 GPa (nano-matrix) whereas that of Al 85 Fe 15 alloys produced in a similar manner was 4.94 GPa (amorphous) and 5.79 GPa (nanocrystalline). For the purpose of preserving amorphous structure during compaction, the temperature of 350 C was chosen, while for nanocrystallisation e the temperature of 1000 C, which was usually used in our previous works for consolidation of nanocrystalline powders [19,20,22] or compaction of amorphous ones accompanied by nanocrystallisation [18,23]. The temperature of 350 C, which is about 40 C below the crystallisation onset temperature, was selected on the base of DSC results [18].…”

Nanocrystalline Ni3Al-based alloys obtained by recycling of aluminium scraps via mechanical alloying and consolidation

“…On the other hand, the use of a high pressure and reduction of the exposure time in the high temperature prevents the excessive growth of grains which are still in the nanometer range [9][10][11]. This method of compaction of the milled powders was successfully used to obtain bulk nanocrystalline alloys from Fe-Al powders [9,[21][22][23]. If it is assumed that the grain growth is a diffusional process, then the hindering of the grain growth is a result of the decrease of the diffusion coefficient.…”

“…The compaction of nanocrystalline powders is a very difficult process because it requires the application of high temperature which may cause the grain growth in the material. However, the simultaneous application of high pressure could inhibit the grain coarsening tendency [9][10][11].…”

Modification of Surface Layers by Surfacing Intermetallic Coatings with Variable Properties

“…Modification of the coating layers using the surfacing of intermetallic coatings might be one of the required methods [4][5][6][7]. The given technology was first developed at Yuri Gagarin State Technical University of Saratov and went through the experimental pre-check needed to produce new and restore worn-out parts of vehicles.…”