Abstract
Composite material prepared by spark plasma sintering (SPS) from a powder mixture of AlCrFeSi rapidly solidified alloy and 5 wt. % of Ni particles was studied in this work. It was proven that during SPS compaction at 500 °C, no intermetallic phases formed on the surface of Ni particles. The material exhibited sufficient mechanical properties obtained by tensile testing (ultimate tensile stress of 203 ± 4 MPa, ductility of 0.8% and 0.2% offset yield strength of 156 ± 2 MPa). Tensile samples were pre-stressed to 180 MPa and annealed at 450 and 550 °C for 1 h. Annealing at 450 °C did not lead to any recovery of the material. Annealing at 550 °C caused the full recovery of 0.2% offset yield strength, while the ductility was decreased. The self-healing behaviour originates from the growth of intermetallic phases between the Ni particle and the Al matrix. The sequence of NiAl, Ni2Al3 and NiAl3 intermetallic phases formation was observed. In particular, the morphology of the NiAl3 phase, growing in thin dendrites into the Al matrix, is suitable for the closing of cracks, which pass through the material.
Highlights
Self-healing materials are designed in order to enrich structural materials by the ability of closing crack that was formed during material utilization
Bulk sintered material was composed of Al matrix, Al13 Cr2 and Al13 Fe4 intermetallic phases and
AlCrFeSi + Ni composite material was successfully prepared by the spark plasma sintering (SPS) process
Summary
Self-healing materials are designed in order to enrich structural materials by the ability of closing crack that was formed during material utilization. Composite materials with the shape memory alloy (SMA) reinforcement and the matrix with off-eutectic composition were described in [6,7] In this case, the phase transformation of the SMA (smart material, in this case shape memory alloy) reinforcement leads to the crack closing and a partial matrix melting heals the already closed crack. The phase transformation of the SMA (smart material, in this case shape memory alloy) reinforcement leads to the crack closing and a partial matrix melting heals the already closed crack Another type of the self-healing behaviour leading to crack closing was observed in Al-Ag alloy, where the phase transformation was between the Ag2 Al phase and the fcc-Al [8]. The low melting healing agent will fill the crack and the hollow diffusion barrier remains as a spherical pore in the microstructure
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