Temperature-dependent tribological properties of low-energy N-implanted V5Ti alloys

2004 ◽  
Vol 188-189 ◽  
pp. 459-465 ◽  
Author(s):  
J.A. García ◽  
G.G. Fuentes ◽  
R. Martínez ◽  
R.J. Rodríguez ◽  
G. Abrasonis ◽  
...  
Keyword(s):  
Tribological Properties ◽  
Low Energy ◽  
Temperature Dependent

Temperature-Dependent Tribological Improvements in Low-Energy Nitrogen Ion Implanted Vanadium-Titanium Alloys

2005 ◽  
Author(s):  
C. Ballesteros ◽  
J. A. Garci´a ◽  
M. I. Orti´z ◽  
R. Rodri´guez ◽  
M. Varela
Keyword(s):  
Tribological Properties ◽  
Low Energy ◽  
Temperature Dependent ◽  
Structural Modifications ◽  
Nanocomposite Layer ◽  
Implantation Temperature ◽  
Transmission Electron ◽  
Nitrogen Ion ◽  
Tribological Characterization

A detailed tribological characterization of low-energy, nitrogen implanted V5 at. %Ti alloy is presented. Samples were nitrogen-implanted at an accelerating voltage of 1.2 kV and 1 mA/cm2, up to a dose of 1E19 ions/cm2. The tribological properties of the alloys: microhardness, friction coefficient and wear resistance, have improved after ion implantation and this improvement increases as the implantation temperature increases. The microstructure of the alloys were analysed by transmission electron microscopy. A direct correlation between structural modifications of the nitrogen implanted layer and the improvement in their tribological properties is obtained. For samples implanted at 848 K a nanocomposite layer where the reinforcement particles are TiN precipitates forms. TiN precipitation appears as the responsible of the improvement in the tribological properties.

scholarly journals SPONTANEOUS PHYSICAL COMPACTIFICATION OF THE EXTRA DIMENSIONS

2001 ◽  
Vol 16 (36) ◽  
pp. 2327-2333
Author(s):  
TIANJUN LI
Keyword(s):  
Symmetry Breaking ◽  
Extra Dimensions ◽  
High Energy ◽  
Energy Scale ◽  
Low Energy ◽  
Temperature Dependent ◽  
Supergravity Theory ◽  
Brane Model ◽  
High Energy Scale ◽  
Bulk Cosmological Constant

We conjecture that the extra dimensions are physical noncompact at high energy scale or high temperature; after the symmetry breaking or cosmological phase transition, the bulk cosmological constant may become negative, and then, the extra dimensions may become physical compact at low energy scale. We show this in a five-dimensional toy brane model with three parallel three-branes and a real bulk scalar whose potential is temperature-dependent. We also point out that after the global or gauge symmetry breaking, or the supersymmetry breaking in supergravity theory, the spontaneous physical compactification of the extra dimensions might be realized.

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