•Graphite substitution by CNTs produced hardened alloys.•CNTs addition induce a reduction of growth rate and porosity of sintered samples.•The equiatomic composition can lead to the generation of ...superior materials.•Coexistence of austenite and Ti-rich phases produced hardened samples.
In the steel industry, the fabrication of sintered products includes the use of graphite as an alloying element and lubricant. This study explores the idea that a sintered alloy with increased properties can be produced substituting graphite by carbon nanotubes. Also, the microstructural characteristics of an equiatomic alloy CrFeMnNiTi were compared with an austenitic 321 stainless-steel; which at present, has a vital role in the food industry. Results showed that the equiatomic alloy was composed mainly by austenite and Ti-rich phases, growth rate and porosity of samples were reduced with the graphite substitution. On this way, carbon nanotubes addition and modification of the chemical composition of the alloy represented viable routes to obtain new alloys with enhanced properties to replace conventional steels.
The effect of graphite, CeO2 and nanohybrid CeO2-graphite on an Al–Mg–Si system (6063 alloys) was studied in this paper. Such alloy was reinforced using mechanical milling, followed by a conventional ...sintering process. Studies for structure, microstructure, and mechanical properties were carried out through X-ray diffraction, electron microscopy, and compression and Vickers microhardness testing. Results showed that the milling process enables homogeneous dispersion of the different reinforcement materials in the Al–Mg–Si matrix. The best performance, concerning reinforcement capacity and microhardness, was obtained with samples reinforced with graphite. The mechanisms involved in enhancing the mechanical properties were active and latent. The first includes grain-size refinement and strengthening by dispersion of a second phase, and the second is related to thermal mismatch.
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•The Gr, CeO2, and nanohybrid CeO2-Gr reinforcements were homogeneously dispersed.•The reinforcements containing Gr presented the formation of Al4C3 during sintering.•The CeO2 presented a partial reduction into Ce7O12 during sintering.•The reinforcements containing Gr showed the best mechanical response.•The active and latent strengthening mechanisms enhanced the mechanical properties.
•Synthesis of 2024-SiCNP nanocomposite by mechanical milling process.•SiC nanoparticles improved mechanical properties of aluminum alloy 2024 matrix.•A homogeneous distribution of SiC nanoparticles ...were observed in the matrix•Compressive and hardness properties of the composite are improved significantly.
Al2024 alloy was reinforced with silicon carbide nanoparticles (SiCNP), whose concentration was varied in the range from 0 to 5wt.%; some composites were synthesized with the mechanical milling (MM) process. Structure and microstructure of the consolidated samples were studied by X-ray diffraction and transmission electron microscopy, while mechanical properties were investigated by compressive tests and hardness measurements. The microstructural evidence shows that SiCNP were homogeneously dispersed into the Al2024 alloy using high-energy MM after 2h of processing. On the other hand, an increase of the mechanical properties (yield stress, maximum strength and hardness) was observed in the synthesized composites as a direct function of the SiCNP content. In this research several strengthening mechanisms were observed, but the main was the obstruction of dislocations movement by the addition of SiCNP.
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