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The diffusion of hydrogen in titanium and phase transitions of simulation and experimental study

Author: LiZuoQi
Tutor: ZhouZuo
School: Nanjing University of Aeronautics and Astronautics
Course: Mechanical Design and Theory
Keywords: Titanium Hydrogen Diffusion Phase transition Mechanical behavior Dynamics database
CLC: TG146.23
Type: Master's thesis
Year: 2009
Downloads: 116
Quote: 3
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Abstract


Titanium and titanium alloy with high strength, good toughness, heat resistance, corrosion resistance, good biocompatibility, etc. become indispensable in many areas of materials, but poor machinability, high processing costs have become obstacles to their wider application . Titanium powder metallurgy is used to reduce processing costs as a potential method; while the hydrogen treatment of titanium for heat processing of titanium is significantly improved properties, thereby further reducing processing costs. In this paper, using the simulation method combined with experiments on hydrogen in titanium particles and plates of diffusion and phase transition process, understanding the diffusion of hydrogen in titanium and phase transition mechanism for the precise control of thermal hydrogen treatment provide a theoretical basis. First, this paper analyzed at different titanium predecessors on hydrogen (hydrogen) phase diffusion mechanism and the diffusion coefficient of the research results obtained hydrogen in α and β titanium titanium existing optimal diffusion coefficient and diffusion mechanisms realistic and fitting out of titanium hydride hydrogen diffusion coefficient. Further according to the determined type of titanium hydrogen (H) phase diffusion coefficient and mechanisms Kinetic edited database of titanium hydride. Combined with Thermo-calc titanium-based alloys developed thermodynamic database - TTTI3, titanium particles on hydrogen charging, dehydrogenation process and the different hydrogen content of titanium particles and plate between the hydrogen diffusion and phase transition process carried out computer simulations, and use a vacuum Experimental verification of the simulation results dehydrogenation. Summarizes the characteristics of different temperatures, titanium particles hydrogen charging, dehydrogenation and particles, the characteristics of the titanium sheet between the diffusion, while the hydrogen diffusion process at different temperatures, the distribution of hydrogen in the titanium and phase transitions were analyzed. Because the simulation of hydrogen required for the mass transfer coefficient on the titanium surface is currently no data available literature references, this article uses a fluidized bed furnace for hydrogen content 0.003wt% of titanium at a constant temperature, the external circumstances hydrogen concentration of hydrogen permeation, LECO GD-OES with measured hydrogen concentration distribution of titanium in. By comparing various hydrogenation hydrogen concentration after time distribution curve calculated on the titanium surface of the hydrogen mass transfer coefficient. It also compares the hydrogen content of the experiment ordinary titanium with different mechanical properties of titanium powder, titanium powder was found by the pressing and sintering of titanium rolling from titanium and general stress-strain curve differ greatly, with hydrogen content increases, the titanium powder metallurgy (H) panels rather soft. In providing a viable thermodynamic and kinetic databases case, the paper compiled for the current system can be used for any solid state diffusion process - gaseous diffusion system.

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CLC: > Industrial Technology > Metallurgy and Metal Craft > Metallurgy and Heat Treatment > Metallic materials > Non - ferrous metals and their alloys > Light non-ferrous metals and their alloys > Titanium
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