In Situ Synthesis of Ti₅Si₃ Matrix Nanocomposites Reinforced with Nanoparticles by High‐Energy Mechanical Alloying

Abstract

In the present work, in situ TiN/Ti5Si3 nanocomposite powder was prepared by high‐energy mechanical alloying of a Ti and Si3N4 powder mixture via the following route: 9Ti + Si3N4 = Ti5Si3 + 4TiN. Constitution phases and microstructural features of the milled powders at different milling times were studied by XRD, SEM, and TEM. The operative formation mechanisms behind the microstructural developments were disclosed. It showed that the original Si3N4 and Ti constituents demonstrated two different reaction mechanisms during milling, i.e., a progressive mechanism of Si3N4 (≤20 h) and a speedy mechanism of Ti (≤10 h). The morphologies of the milled composite powders experienced a successive change: pre‐refining – coarsening – re‐refining on increasing the applied milling time. The variation of the operative mechanisms was ascribed to the existence/exhaustion of the ductile Ti constituent in the milling system due to the nonoccurrence/initiation of the in situ reaction. The 20 h milled powder was the typical nanocomposites featured by the nanocrystalline Ti5Si3 matrix reinforced with in situ TiN nanoparticles. The grain sizes of the in situ formed Ti5Si3 and TiN phases were generally ≤15 nm, exhibiting coherent interfacial structure between reinforcement and matrix.

Metal matrix to ceramic matrix transition via feedstock processing of SPS titanium composites alloyed with high silicone content

“…The preparation of the powder samples suitable for subsequent SPS processing was aimed at obtaining well-mixed blends of Ti and Si components with a variation in the particle size and morphology. As shown by XRD patterns, the formation of titanium silicides (as observed during mechanical alloying of Ti/Si 3 N 4 powders (Li et al 2011)) or other undesirable phases (such as titanium oxides, nitrides or carbides) which can strongly affect the microstructure and the mechanical properties of synthesized composites was avoided during the mixing/milling of the powders. The TS-3 mixture indicated a possible refinement and/or nano-structurization of the Ti and Si powder particles, as evidenced by the strong Ti and Si diffraction peak broadening and the decrease in the peaks intensities.…”

Hallmarks of mechanochemistry: from nanoparticles to technology

“…29 Steps of powder evolution during mechanical alloying: 1 -initial powders, 2 -flattering, 3 -welding, 4 -3D welding and fracturing, 5 -stable end product. 194 ceramic-dispersed phases like TiC, [504][505][506][507][508][509] TiB, 510,511 BN, 512 carbon nanotube, 513,514 fullerene, 515 ZrO 2 , 516 TaC, 517 NbC, 518 TiN, 519 Cr 2 O 3 , 520 SiC 521 or WC 522,523 with a noticeable improvement of the mechanical properties.…”

Retracted: Effect of High‐Energy Electropulsing on the Phase Transition and Mechanical Properties of Two‐Phase Titanium Alloy Strips

“…Especially in the biomedical application, the plasticity in the usage and processing is very significant. However, the difficulty in the forming and processing the materials in the ambient or low‐temperature conditions is the major obstacle for widespread applications of titanium alloys . Gurao et al .…”