Growth of normally-immiscible materials (NIMs), binary alloys, and metallic fibers by hyperbaric laser chemical vapor deposition

Maxwell, James; Black, Marcie R.; Chavez, Craig; Maskaly, Karlene Rosera; Espinoza, Miguel; Boman, Mats; Landström, Lars

doi:10.1007/s00339-008-4440-3

Cited by 7 publications

(6 citation statements)

References 34 publications

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“…Firstly, grain refinement reduces the sliding displacement of dislocations inside the grains and makes tensile deformation more uniformly. In addition, grain boundary sliding and rotation of small grains favorably accommodates the local strain near the large grain boundaries [20]. Thus, stress concentration can be released by grain boundary sliding and rotation of the small grains surrounding the large grains.…”

Section: Mechanical Properties Microstructure and Tensile Fracture Bmentioning

confidence: 98%

Enhancement of ductility, weakening of anisotropy behavior and local recrystallization in cold-rolled Ti-6Al-4V alloy strips by high-density electropulsing treatment

Yang

Song

et al. 2014

Appl. Phys. A

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The effect of high-density electropulsing treatment (EPT) on the microstructure, mechanical properties and fracture behavior of cold-rolled Ti-6Al-4V alloy strip was investigated. The results indicated that EPT accelerated the local recrystallization process tremendously in predeformed titanium alloy. The EPT-induced microstructural change resulted in remarkably increasing elongation to failure while remained tensile strength unchanged. In addition, anisotropy behavior of mechanical property is weakened dramatically. A mechanism for rapid local recrystallization in low temperature during EPT was proposed based on the reduction of nucleation thermodynamic barrier and enhancement of atomic diffusion. Uneven fractures of different direction specimens with quasi-cleavage fracture mode were gradually evolved into uniform ductile fracture mode with transgranular dimples under EPT.

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Section: Mechanical Properties Microstructure and Tensile Fracture Bmentioning

confidence: 98%

Enhancement of ductility, weakening of anisotropy behavior and local recrystallization in cold-rolled Ti-6Al-4V alloy strips by high-density electropulsing treatment

Yang

Song

et al. 2014

Appl. Phys. A

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“…Observe that with each increase in base pressure an increase in axial growth rate occurs (as expected from previous results using only natural convection). 9,18,23,50 In addition, the forced flow of precursor through the nozzle enhances the axial growth rate by a factor of at least 1.5 over the measured range, and if extrapolated to the zero-flow y-intercept, at least 2-3 times. Clearly, growth rate enhancements are indeed possible using transverse forced flow in the configuration of Figure 3(a).…”

Section: Experimental Forced-flow Measurementsmentioning

confidence: 95%

“…[4][5][6][7][8][9][10] At sufficiently high deposition rates, if the laser focus is stationary, the deposit may grow away from the substrate and along the laser beam axis, forming a freestanding fiber. [11][12][13][14][15][16][17][18][19][20][21][22][23] If the orientation and position of the beam is changed slowly relative to the sample during growth, complex three-dimensional structures may be grown in a freeform manner. [24][25][26][27][28][29] This process is of importance to the textile industry, as novel materials can now be grown at rapid rates-in the form of fibers.…”

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confidence: 99%

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On “how to start a fire”, or transverse forced-convection, hyperbaric laser chemical vapor deposition of fibers and textiles

Maxwell

Webb

Bradshaw

et al. 2014

Textile Research Journal

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This work explores the transverse forced flow of precursor gases during hyperbaric pressure laser chemical vapor deposition (HP-LCVD). Axial and mass growth rates of carbon fibers are measured experimentally, and a numerical model is developed that provides fiber growth rates in both the mass-transport-limited (MTL) and kinetically limited (KL) regimes. It is found that the fiber’s transport-limited rate increases as the square root of the flow velocity, while simultaneously, the temperature drops with the inverse square root of the flow velocity. Growth is enhanced by forced flow so long as the reaction zone remains within the MTL regime; upon reaching a critical temperature and flow rate, however, fibers enter the KL regime, and the growth rate declines with rising flow rate. Molecular properties of the precursors employed and gas concentrations ultimately determine the range of the MTL and the locations of the critical temperature and flow rate. The growth rates of fibers can indeed be enhanced by transverse forced convection—to at least three times the zero-flow steady-state rate, provided an MTL regime exists. Complex three-dimensional structures may be grown from these fibers in a freeform manner, and the more rapidly such microstructures can be fabricated, the more practical HP-LCVD becomes for industrial use, including the fabrication of novel textiles.

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“…Among them, TiCl 4 exhibits relatively simple vapor deposition chemistry and excellent thermal stability, and, hence, it does not readily decompose in the gas phase. In addition, TiCl 4 has a higher vapor pressure than other halides, including fluorides, bromides, and iodides and hence exists in a liquid phase at room temperature [22]. It is, therefore, a good precursor candidate for the CVD/ALD technique [23].…”

Section: Introductionmentioning

confidence: 99%

Adsorption of Titanium Halides on Nitride and Oxide Surfaces during Atomic Layer Deposition: A DFT Study

Park

Jang

et al. 2020

Coatings

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Various processes based on atomic layer deposition (ALD) have been reported for growing Ti-based thin films such as TiN and TiO2. To improve the uniformity and conformity of thin films grown via ALD, fundamental understanding of the precursor–substrate surface reactions is required. Herein, we present a density functional theory (DFT) study of the initial nucleation process of some titanium halide precursors (TiCl4, TiBr4, and TiI4) on Si surfaces having –OH or –NH2 functional groups. We consider the most favorable adsorption site in the reaction between the precursor and functional group of the surface, based on the thermodynamics and kinetics of the reaction. Sequential dissociation reaction mechanisms of halide ligands were systematically investigated. The exothermicity of the dissociative adsorption was found to be in the order of: TiI4 > TiBr4 > TiCl4. In addition, the precursors were observed to be more exothermic and show higher reaction rate constant when adsorbed on the –OH–terminated surface than on the –NH2–terminated surface. These observations reveal the selectivity of deposition by surface functional groups.

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Growth of normally-immiscible materials (NIMs), binary alloys, and metallic fibers by hyperbaric laser chemical vapor deposition

Cited by 7 publications

References 34 publications

Enhancement of ductility, weakening of anisotropy behavior and local recrystallization in cold-rolled Ti-6Al-4V alloy strips by high-density electropulsing treatment

Enhancement of ductility, weakening of anisotropy behavior and local recrystallization in cold-rolled Ti-6Al-4V alloy strips by high-density electropulsing treatment

On “how to start a fire”, or transverse forced-convection, hyperbaric laser chemical vapor deposition of fibers and textiles

Adsorption of Titanium Halides on Nitride and Oxide Surfaces during Atomic Layer Deposition: A DFT Study

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