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Yang R.,University of Sichuan | Xing T.,State Key Laboratory of Nonferrous Metals and Processes | Xu R.,Wuhan University of Science and Technology | Li M.,University of Sichuan
International Journal of Refractory Metals and Hard Materials | Year: 2011

A novel method for synthesizing ceramic powders in molten salt was introduced in this paper. Unlike traditional mechanochemical process, the novel method is based on mechanical alloying followed by chemical reaction in liquid phase (molten salt). The reaction temperature to synthesize tungsten carbide in molten salt was 1000 °C. Results in this paper showed that W 2C and WC powder could be successfully synthesized by the method. Under raised reaction conditions, there was a transformation from W 2C to WC. The mechanism of the reaction in molten salt was discussed finally. © 2010 Elsevier Ltd. All rights reserved.

Xing T.,State Key Laboratory of Nonferrous Metals and Processes | Xing T.,University of Alberta | Cui X.,University of Alberta | Chen W.,University of Alberta | And 2 more authors.
Materials Chemistry and Physics | Year: 2011

Porous chromium carbide structures have been synthesized through reactive sintering of chromium oxides in carbonaceous reducing environments. The process is simple and can be used to fabricate large size porous structures. It has been characterized that the pores in the porous structure are open in nature and the size of pores in the same porous structure can be controlled within a narrow range. Depending on the processing condition, the porosity in the porous structure was measured to be from 50% to 78%, and pore size varied from 0.5 μm to 3 μm. It has been determined that the porosity in the process was formed primarily due to volume reduction caused by phase transformation from chromium oxides to chromium carbides. It is believed that similar process can be used to form porous structures of other materials as long as a reactive sintering can occur and is accompanied with volume reduction. © 2011 Published by Elsevier B.V.

Xing T.,State Key Laboratory of Nonferrous Metals and Processes | Yang R.,University of Sichuan | Zheng Y.,China University of Petroleum - East China | Cui L.,China University of Petroleum - East China | Mi X.,State Key Laboratory of Nonferrous Metals and Processes
Materials Transactions | Year: 2011

This work is focused on the influence of cold-rolling on the transformation and internal friction behavior of TiNi shape memory alloy. The DSC results show the endothermic peaks disappeared with the increasing of cold-rolling reduction and there was an exothermic peak around 330°C on the curve during the first heating process. The exothermic peak is associated with recrystallization of amorphous phase induced by cold-rolled work. During the second heating process, the endothermic peak showed up but the exothermic peak didn't. These phenomena are confirmed by the internal friction results. During the first heating process, the transformation internal friction decreased with the increasing of the cold-rolling reduction and the internal friction augmentation appeared around 330°C which is related to recrystallization. © 2011 The Japan Institute of Metals.

Xing T.,State Key Laboratory of Nonferrous Metals and Processes | Mi X.,State Key Laboratory of Nonferrous Metals and Processes | Yin X.,State Key Laboratory of Nonferrous Metals and Processes | Gao B.,State Key Laboratory of Nonferrous Metals and Processes | Li Y.,State Key Laboratory of Nonferrous Metals and Processes
Advanced Materials Research | Year: 2011

The objective of this work is to investigate the influence of measuring frequency on the internal friction of Ti50Ni48.5Fe1.5 shape memory alloy. The DSC, DC electrical resistivity and internal friction measurements were employed to characterize the sample in this study. Comparing the DSC result, the two internal friction peaks were confirmed which are corresponding to the R-phase transformation and martensitic transformation of Ti50Ni48.5Fe1.5 alloy during the cooling process, respectively. The height of internal friction peak corresponding to martensitic transformation increased with decreasing of measuring frequency. But, the height of the internal friction peak corresponding to R-phase transformation exhibited little measuring frequency dependence. Meanwhile, the value of the relative modulus peaks of the specimen increased with measuring frequency increasing. Furthermore, there was an interesting phenomenon that the martensitic transformation finish temperature shifted to higher temperature side with increasing of measuring frequency. It could be associated with the variation of applied vibration energy. © (2011) Trans Tech Publications.

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