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

Abstract

At present, metallic glasses are evaluated as alternative reinforcements for aluminum matrix composites. These composites are produced by powder metallurgy via consolidation of metallic glass-aluminum powder mixtures. In most studies, the goal has been to preserve the glassy state of the reinforcement during consolidation. However, it is also of interest to track the structure evolution of these composites when partial interaction between the matrix and the metallic glass is allowed during sintering of the mixtures. The present work was aimed to study the microstructure and mechanical properties of composites obtained by spark plasma sintering (SPS) of Al-20 vol.% Fe66Cr10Nb5B19 metallic glass mixtures and compare the materials, in which no significant interaction between the matrix and the Fe-based alloy occurred, with those featuring reaction product layers of different thicknesses. Composite materials were consolidated by SPS at 540 and 570 °C. The microstructure and mechanical properties of composites obtained by SPS and SPS followed by forging, composites with layers of interfacial reaction products of different thicknesses, and metallic glass-free sintered aluminum were comparatively analyzed to conclude on the influence of the microstructural features of the composites on their strength.

Core–Shell Particle Reinforcements—A New Trend in the Design and Development of Metal Matrix Composites

“…Shells forming in situ upon the interaction of the embedded particles with the matrix can be of complex composition when alloys are taken instead of single-phase metals. For example, in our work, after SPS of an Al-20 vol.% Fe 66 Cr 10 Nb 5 B 19 mixture [ 14 ], the shell forming on the Fe-based alloy particles had a gradient structure ( Figure 3 ) and contained both iron and chromium.…”

“…The in situ formation of core–shell reinforcements has been realized by a number of methods, including solid state sintering of powder mixtures under pressure [ 11 , 12 , 13 , 14 ], solid state sintering under pressure followed by hot deformation processing [ 15 ] (a combination with pre-heating [ 16 ] or post-deformation annealing [ 9 ] is possible), sintering of previously obtained metal@metal core–shell particles with an additional amount of the powder of the matrix [ 21 ], a solid state reaction between metallic rods and the surrounding matrix [ 19 , 20 ], thixoforming [ 22 , 23 , 24 ], friction stir processing followed by annealing [ 25 ], modification of a pre-existing skeleton followed by infiltration [ 26 ], a reaction between solid particles with a metallic melt [ 27 ] and a synthesis in a metallic melt from the added reactants [ 18 ].…”

“…[ 14 ], a high compressive strength of an Al-based composite was achieved by forming a thick shell, which, at the same time, deteriorated plasticity. Figure 5 a shows the microstructure of the composite obtained by SPS of an Al–20 vol.% Fe 66 Cr 10 Nb 5 B 19 glassy alloy powder mixture [ 14 ]. The products of the interaction between aluminum and the metallic glass are Al-Fe-Cr intermetallics.…”

“… ( a ) Microstructure of the composite obtained by spark plasma sintering of Al-20 vol.% Fe 66 Cr 10 Nb 5 B 19 powder mixture, 540 °C, 3 min, ( b ) Fe-based alloy particle in an Al matrix, and results of the energy-dispersive spectroscopy analysis along the red line on the image. Reprinted from [ 14 ]. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ( , accessed on 10 March 2022).…”

“…The core materials can be of different compositions: single metal [ 9 ], MXene phase [ 10 ], metal-ceramic composite [ 11 ], intermetallic phase [ 12 ], glassy alloy [ 13 , 14 , 15 ], high-entropy alloy [ 16 , 17 ] or carbon [ 18 ]. Shells forming in situ in the cases of metal (metal-containing) cores are of intermetallic or solid solution nature.…”