Interaction between Fe66Cr10Nb5B19 metallic glass and aluminum during spark plasma sintering

Abstract

In the area of metal matrix composites, novel reinforcing options are currently being evaluated. Particles of amorphous alloys present an interesting possibility to reinforce soft metals. In the present work, the interaction between Fe66Cr10Nb5B19 metallic glass and aluminum during Spark Plasma Sintering (SPS) was studied for the first time. In order to trace the phase and microstructural changes upon sintering, mixtures containing 20 vol.% and 50 vol.% of metallic glass were subjected to SPS at 500-570 ºC. After SPS at 500 ºC, no reaction layer between the metallic glass particles and aluminum was observed. After SPS at 570 ºC, a reaction layer containing Fe2Al5 and FeAl3 formed around the Fe-based cores. The Vickers hardness of composites obtained from mixtures containing 20 vol. % Fe66Cr10Nb5B19 at 540 ºC was 75 HV and increased to 280 HV after sintering at 570 ºC due to the formation of thicker reaction layers at the interface.The hardness of the composite sintered from the mixture containing 20 vol. % Fe66Cr10Nb5B19 at 570 ºC was between the values predicted by Reuss and Voigt models.Comparison of results of SPS of the powder mixtures with those of SPS of a precompacted pellet and electric current-free annealing suggests that local heating at the interface caused by interfacial resistance may be an important factor influencing the reaction advancement at the interface and the formation of Al-containing intermetallics.

Microstructure and Mechanical Properties of Composites Obtained by Spark Plasma Sintering of Al–Fe66Cr10Nb5B19 Metallic Glass Powder Mixtures

“…Indeed, the Fe 66 Cr 10 Nb 5 B 19 powder is predominantly amorphous: the concentration of the crystalline phase (body-centered cubic iron) is~5 wt.%, as determined in our previous work [22]. The glass transition temperature and crystallization temperature of the glassy phase in the Fe 66 Cr 10 Nb 5 B 19 alloy is 521 and 573 • C, respectively [13].…”

“…In the present study, gas-atomized powders of Fe 66 Cr 10 Nb 5 B 19 , <45 µm fraction [13] and aluminum were used. The Al powder had a purity of 99.9% (PAD-6, average particle size 6 µm, "VALKOM-PM", Volgograd, Russia).…”

“…Recent years have seen active research in the area of aluminum matrix composites directed at evaluating the suitability of alternative (non-ceramics) reinforcements. In novel composites, particles of intermetallics [2,3], quasicrystals [4], high-entropy alloys [5,6], or metallic glasses [7][8][9][10][11][12][13][14] are used as the reinforcing elements. These composites are usually produced by powder metallurgy via consolidation of mixtures of the matrix metal and metallic alloy powders.…”

“…Fe-based metallic glasses are known for their high hardness and corrosion resistance [18]. Fe 66 Cr 10 Nb 5 B 19 amorphous alloy powders are easily obtained by gas atomization using commercial alloys as raw materials [13]. This makes Fe 66 Cr 10 Nb 5 B 19 alloy powders with a glassy structure attractive for the reinforcing purposes.…”

“…Our previous study reported the hardness of composites obtained by SPS of Al-Fe 66 Cr 10 Nb 5 B 19 mixtures and the microhardness of separate phases [13]. The present work was aimed to study the microstructural features and mechanical properties of composites obtained by SPS of Al-20 vol.% Fe 66 Cr 10 Nb 5 B 19 mixtures and compare composites, in which no significant interaction between the matrix and the Fe-based alloy occurred, with those featuring reaction product layers of different thicknesses.…”