Papers by Keyword: In Situ Reaction

Abstract: In this work, in-situ TiC reinforced Ti matrix composites (TMCs) have been fabricated via blending TiH₂ powder and multi-walled carbon nanotubes (CNTs) followed by thermomechanical consolidation of the TiH₂/CNTs powder mixture. The dehydrogenation, in situ reaction and consolidation occurred simultaneously and took less than 15 minutes in total. The effect of CNTs content (1 and 3 vol.% (0.56 and 1.69 wt.%)) on the evolution of microstructures and mechanical performances of the extruded samples has been investigated. The results showed that the extruded TMCs had a duplex microstructure consisting of coarse alpha titanium grains and ultrafine grained (UFG) regions, and the in-situ formed TiC particles had a near-spherical shape. The extruded sample with 1 vol.% (0.56 wt.%) CNTs reinforced exhibited a yield strength of 807.3 MPa, ultimate tensile strength of 1085.9 MPa and elongation to fracture of 3.3% at room temperature. The mechanism of microstructural evolution and material failure are discussed.e are discussed.

Abstract: An innovative spray deposition technique has been applied to produce in situ TiB₂/Zn-30Al-1Cu composites. The microstructures of the spray-deposited composite were studied using optical microscopy, scanning electron microscopy, and X-ray diffraction. Both theoretical and experimental results have shown that the TiB₂ particulates are formed in the microstructure. It was found that the TiB₂ particles were distributed in Zn-30Al-1Cu matrix uniformly, and the TiB₂ particles are about 2 μm in size. Moreover, the presence of the TiB₂ particles was led to increasing of α’ phase with less 2 μm size in the composites which have a tendency to decompose to α+η structure.

Abstract: Hollow silica microspheres with porous surface were synthesized by using the pollen grains as biotemplate through an in-situ synthesis process, in which the pollen grains were surface modified by ammonium oleate. Scanning electron microscopy, Fourier transform infrared spectroscopy and nitrogen adsorption-desorption porosimetry analyzer were applied to investigate the as-prepared microspheres. Bovine serum albumin was used as the model drug to estimate the adsorption property. And the effect of the different amount of tetraethoxysilane during the synthesis process were discussed in this paper. Results indicated that the hierarchical network of the pollen wall could be well replicated through this method, in which the hydrophobic interaction between the pollen wall and surfactant as well as the electrostatic interaction between the surfactant and the hydrolysate of tetraethoxysilane were considered as the key factors for the replication. The hollow silica microspheres have loading capacity for the model drug, and the adsorption property of this microsphere could be easily adjusted by changing the amount of tetraethoxysilane.