Aluminum A356 Reinforcement by Carbide Nanoparticles

2011 ◽  
Vol 13 ◽  
pp. 41-46 ◽  
Author(s):  
Konstantin Borodianskiy ◽  
Michael Zinigrad ◽  
Aharon Gedanken

The main issue of the study is aluminum A356 alloy modification by TiC nanoparticles process. Nanoparticles of TiC were especially mechanochemically activated to remove the oxide layer on the particle surface in order to prevent its floating on the molten metal surface. Experimental results indicate that after T6 heat treatment the tensile strength of the modified alloy increased by 6.5%, yield strength increased by 9% and the elongation increased by 22%. A high resolution electron microscopy study shows that dislocation of the modified alloy concentrates near the grain boundary during the crystallization process, and these grain boundaries act as obstacles to dislocation motion. Based on these results, it was found that grain-size aluminum strengthening mechanism occurs in the nanoparticle carbide reinforcement process.

1980 ◽  
Vol 2 ◽  
Author(s):  
Fernando A. Ponce

ABSTRACTThe structure of the silicon-sapphire interface of CVD silicon on a (1102) sapphire substrate has been studied in crøss section by high resolution transmission electron microscopy. Multibeam images of the interface region have been obtained where both the silicon and sapphire lattices are directly resolved. The interface is observed to be planar and abrupt to the instrument resolution limit of 3 Å. No interfacial phase is evident. Defects are inhomogeneously distributed at the interface: relatively defect-free regions are observed in the silicon layer in addition to regions with high concentration of defects.


1993 ◽  
Vol 8 (11) ◽  
pp. 2893-2901 ◽  
Author(s):  
M. Catalano ◽  
M.J. Kim ◽  
R.W. Carpenter ◽  
Das K. Chowdhury ◽  
Joe Wong

The nanostructure and chemical distribution in semi-insulating polycrystalline oxygen-doped silicon (SIPOS) deposited on (001) Si and its isothermal transformation behavior at 900 °C were investigated by high resolution electron microscopy (HREM) and electron energy loss nanospectroscopy (EELS). The structure of the as-deposited film, which contained 15 at. % oxygen, was amorphous. No evidence for nanocrystalline second phases was found. It was similar in appearance to amorphous silicon. After annealing for 30 min at 900 °C in an inert environment (N2), a dispersion of small nanocrystals, identified as silicon by imaging, diffraction and EELS, formed in the amorphous SIPOS matrix, with a thin precipitate free zone (PFZ) adjacent to the Si substrate. The SIPOS matrix oxygen concentration increased to 36 at. % and the matrix remained amorphous after annealing. No other phases were observed in annealed specimens. Changes in Si–L near edge fine structure and low loss peaks in EELS spectra from SIPOS with increasing oxygen concentration indicated that it is a solid solution supersaturated with silicon. Microstructures indicated that the Si nanocrystals formed during a homogeneous precipitation reaction.


1983 ◽  
Vol 76 (2) ◽  
pp. K109-K111 ◽  
Author(s):  
D. Sundararaman ◽  
A. L. E. Terrance ◽  
G. van Teneloo ◽  
J. van Landuyt

Sign in / Sign up

Export Citation Format

Share Document