Papers by Keyword: TiC

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Authors: Zoltán Kálazi, Viktória Janó, Gábor Buza
Abstract: Tungsten (W) based alloy composite layer reinforced with TiC particles has been successfully prepared on unalloyed steel sample by LMI technology. In order to obtain in situ produced TiC reinforcement, pure titanium has been introduced to the melt pool. WC powder was added for increasing the carbon content of the layer in order to avoid the softening of the matrix (with low carbon content) during TiC formation. The present study aims to investigate the optimum amount of injected WC and Ti powder to improve wear resistance and hardness of the layer. Samples were investigated using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The maximum hardness of the layer has been reached ~900HV in case of 2-4wt% of titanium content. Ti has been collected all of the carbon from the matrix when titanium content was 9,6wt%, which resulted that the austenite and (Fe,W)6C phases have been disappeared. Only α-Fe and TiC phases were presented in the layer. The hardness of the layer reduced to the hardness of the base material.
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Authors: Ke Tang, Chang An Wang, Ai Guo Zhou, Li Feng Wu, X.L. Xu, Yong Huang
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Authors: Masanori Kohyama, J. Hoekstra
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Authors: Liang Liang Wang, Yun Hua Xu, Li Sheng Zhong
Abstract: An in-situ synthesis process combining an infiltration casting with a following heating treatment was applied to fabricate special titanium carbide (TiC) particles-reinforced iron matrix surface gradient composites in this article. The microstructure and wear-resistance of the titanium carbide particle reinforced iron matrix surface gradient composites were researched by using differential scanning calorimetry, X-ray diffraction, scanning electron microscopy and abrasive wear testing. The results showed that two materials had been reacted completely between the titanium plate and gray cast iron, and the titanium carbide particles distributed in the matrix with the thickness of 266.7 μm reaction layer. The average size of titanium carbide between titanium plate and iron matrix was about 1-2μm. Under the same condition, the wear mechanism of titanium carbide particles-reinforced iron matrix surface gradient composites appeared as: micro-ploughing, micro-cutting and broken titanium carbide.
81
Authors: Zheng Guang Zou, Kai Liu, Yu Fang Shen, Zhi Gang Xiao, Fei Long, Yi Wu
Abstract: This work focus on the effects of C vacancy on wetting of Fe to TiC/Fe at the cermet interfaces. We do the whole work using the first-principles density functional theories. The ideal work of adhesion of the pure interface is not big enough, comparing with the expeimental value. Our calculations suggest that the C vacancy at the interface is a very important factor for interface banding of TiC/Fe cermet composite. An adequate quantities of C vacancies at the interface can improve the wetting of TiC/Fe interfaces.
368
Authors: Wan Wu Ding, Jiang Tao Zhu, Wen Jun Zhao, Tian Dong Xia
Abstract: The grain refining effects of Al-Ti, Al-TiC and Al-Ti-C master alloys on commercially pure aluminum were compared, and the grain refinement mechanism of TiAl3 and TiC among master alloys was discussed. The results show that: the grain refinement of the master alloys Al-TiC and Al-Ti toward pure aluminum mainly stems from the heterogeneous nucleation role of TiC and TiAl3 particles, but with the extension of heat preservation time of fused mass, its role of heterogeneous nucleation will decline due to dissolution of TiAl3 and aggregation and precipitation of TiC. The preferable grain refinement effects of Al-Ti-C master alloys toward pure aluminum are mainly due to the fact that when TiAl3 and TiC particles are acted commonly as heterogeneous nucleation particles, the heterogeneous nucleation effect of TiC particles will be enhanced because of the presence of TiAl3.
1072
Authors: Sayed Hamid Reza Fatemi Nayeri, Jalil Vahdati Khaki, Mohammad Reza Aboutalebi
Abstract: The starting reaction in the combustion synthesis process in TiO2-Al-C system leading to TiC+Al2O3 composite was evaluated using a combination of Differential Thermal Analysis (DTA), X-Ray Diffraction (XRD) and Transmission Electron Microscope (TEM). Double phases in 3TiO2- 4Al-3C system were milled separately and then the third phase was added according to the stoichiometric reaction for 3TiC+2Al2O3 composite formation. The combustion synthesis temperature was observed to decrease from 962 °C to 649 °C after mechanical activation of TiO2/Al mixture for 16 hr. On the contrary, the mechanical activation of Al/C and TiO2/C mixtures for 16 hr made the reaction temperature increase to 995 °C and 1024 °C, respectively. TEM and XRD patterns of as-milled powders showed that the reaction temperature changes could be due to increased TiO2 and Al interface area. In addition, DTA experiments showed that for the sample in which TiO2 and Al were mechanically activated the reaction occurred at the temperature even lower than the aluminum melting point.
210
Authors: Sayed Hamid Reza Fatemi Nayeri, Jalil Vahdati Khaki, Mohammad Reza Aboutalebi
Abstract: A mechanism for the combustion synthesis of TiC+Al2O3 was proposed in a mechanically activated TiO2-Al-C system. As-milled powder mixture was analyzed using XRD and TEM techniques where no chemical reaction and/or inter-particle diffusion were identified. The results obtained from DTA tests on unmilled powder revealed that the combustion synthesis occurred in a single step at 962 °C while the synthesis of mechanically activated powder mixture occurred in three different stages. The XRD analysis on the synthesized samples of 8 hour premilled powder at different temperatures showed that the three stages were as follows: First the reaction between Al and TiO2 takes place forming Al3Ti, Ti2O3, and Al2O3 at 700 °C. In the second step, Ti-rich titanium aluminides (AlTi, AlTi2, and AlTi3) and TiO, are formed at 923 °C, and finally the formation of TiC+Al2O3 is completed at 1329 °C.
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