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The Wear Behaviors and Oxidation Behaviors of TiC/Ti Matrix Composites

Author: WangYuLin
Tutor: LiuYong
School: Central South University
Course: Materials Science
Keywords: TiC in situ generation TiC / Ti matrix composites Wear resistance Oxidation Behavior
CLC: TB331
Type: Master's thesis
Year: 2011
Downloads: 45
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Abstract

Titanium matrix composites with its high specific strength and specific stiffness, excellent wear resistance and resistance to high-temperature properties and caused widespread attention in recent years, the development soon. Generated in situ particle reinforced titanium matrix composites with isotropic and ease of molding, low cost, used widely. With the development of titanium matrix composites, according to the various needs of the practical application of research to its high-temperature oxidation behavior and wear resistance is increasingly important. Enhance the selection phase additives and content of the study from the particles, metal elements and the selection of the alloying elements in the matrix of these two aspects of the composite performance study, prepared by powder metallurgy generated in situ formed TiC / Ti matrix composites using UTM 3 tribometer and high-temperature diffusion furnace temperature oxidation behavior of its friction behavior under different conditions and at different temperatures. X-ray diffraction (XRD), scanning electron microscopy (SEM) spectroscopy (EDX) analysis by means of the phase composition and microstructure of the material. The following conclusions: 1. The friction behavior of the metal carbide powder, the added amount of the 6A1-4V intermediate alloy powder, Al / Sn / Zr metal powder to be added, and the type of metal carbide of TiC / Ti-based composite material has a significant impact . The Mo2C added, can reduce the amount of wear of the α-Ti, improve its abrasion resistance. The VC added amount is smaller, the amount of wear of the α-Ti can be reduced, but increased when the addition amount reached 12%, the wear amount, the wear resistance deteriorates. Add Mo2C composite material wear amount significantly lower than the add the VC composite material. Due to the adhesion of metal such as Sn, Al, Zr and Fe, so that the adhesive wear phenomenon is aggravated, so the added amount of the 6A1-4V alloy powder increase will lead to increase in the amount of wear of the composite material, while adding the TMCs wear of aluminum, tin, zirconium powder the largest amount. 2.TMCs main wear mechanism of adhesive wear, abrasive wear and oxidation wear, its wear resistance is mainly determined by the nature of the matrix. Compared with the V, Mo better solution strengthening effect on the matrix, conducive to improve the wear resistance. Titanium matrix composites add the VC, the toughness of the matrix, generated TiC particle size and dispersion of the distribution, so that the abrasive wear increased, and even lead to three-body abrasion generates. Add Mo2C titanium matrix composites, TiC particles generated relatively large and segregation phenomenon better abrasion resistance. 3 under the same conditions, the add the Mo2C of titanium matrix composite antioxidant activity significantly superior to add VC titanium matrix composites. Ti x% Mo2C titanium matrix composites parabolic oxidation law, different add no significant effect on the oxidation kinetics curves. Ti x% VC titanium matrix composites has nearly linear oxidation law, add the amount of the increase and the temperature rise, the oxidation intensified and eventually oxidized failure. Mo2C and 6A1-4V master alloy powder while adding titanium matrix composites parabola - Linear mixed oxidation law. Adding A1, Sn, Zr metal powder of titanium matrix composites with nearly parabolic oxidation law. 4 types of additives have a major impact on the substrate β-Ti phase and the evolution of the TiC particles in the oxidation process. Β-Ti in the Mo-rich phase in the role of oxygen into the α-Ti phase, and Mo solid solution in the corresponding α-Ti phase, the diffusion of oxygen is suppressed to improve the stability of the reinforcing phase particles, help to improve the oxidation resistance of the material. Rich V, β-Ti phase oxidation product V2O5 highly volatile, so that the oxide layer to produce a large number of micro-cracks, to accelerate the diffusion of oxygen, to provide favorable conditions for the oxidation of the TiC particles. Moreover, V2O5 and CO2 can be discharged through the cracks, so that the oxidation reaction is more easily performed, further reducing the oxidation resistance of the material. Despite can improve the oxidation resistance of Al and Mo2C, but the addition of the V lead to holes and other defects in the oxide layer, therefore add 6A1-4V titanium alloy powder of the middle of its oxidation resistance matrix composites as add the amount of the increase in the worse . Tin, zirconium, aluminum complex using more conducive to hot strength of the alloy, the addition of such metal powder can effectively improve the oxidation resistance of the material.

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