Heat capacity and thermodynamic properties of ditungsten carbide, W2C1-x, from 10 to 1000 K

Thermodynamic properties of tungsten carbide, W2C0.833, have been derived from heat capacities measured by adiabatic calorimetry in the range 10-1000 K on a sample rich in this phase. The standard entropy of W2C0.833 was found to be 75.80 J K-1 mol-1 at 298.15 K and 159.8 J K-1 mol-1 at 1000 K. Thermodynamic formation values for W2C0.833 were deduced from the reported coexistence of this phase with tungsten and tungsten monocarbide at about 1550 K.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27259/1/0000268.pd

Effect of laser irradiation on failure mechanism of TiCp reinforcedtitanium composite coating produced by laser cladding

Laser cladding is an effective technique to coat a metallic substrate with a layer of a different nature.It has been widely reported that the most important combined parameters controlling the quality ofthe coating are the specific energy (E) and the powder density ( ). In the present work, clad depositsof Ti6Al4V + 60 wt.% TiC were prepared on a Ti6Al4V substrate using an optimum combination of Ec= 24 J/mm2 and c= 3 mg/mm2. These experiments were performed using a laser power of 400 and600 W, in order to study the effect of laser power on the properties of the clad. The microstructure, phasecomposition and nanohardness of the coatings were investigated by optical microscopy, scanning elec-tron microscopy and X-ray diffraction. During laser processing, TiC can be partially converted to TiCX(X = 0.5) due mainly to the TiC dissolution into the laser-generated melting pool and subsequent precipi-tation during cooling. It was observed that the lower laser power limit reduces primary TiC dissolution butit also promotes secondary carbide alignment at the interface. On the other hand, the damage mechanisminduced by high laser power is dominated by primary TiC particle cracking by the high stress concentra-tion at the particle matrix interface followed by ductile failure of the matrix. It is also remarkable thatirradiance affects the TiC/TiCxratio despite Ecand care fixed and it determines hardness distributioninside the coating.Authors thank MINECO funding in special the Training of Research Staff programme with the help BES-2009-013589 and the support of the Comision Interministerial de Ciencia y Tecnologia (CICYT), Spain, under Grant MAT2012-39124. This work was developed at the Materials Technology Unit of the Polytechnic University of Valencia associated to CSIC through the National Centre for Metallurgical Research (CENIM). Finally, thank the EU for the funding received through the FEDER help in the project UPOV08-3E-005 for the purchase of equipment and the Generalitat Valenciana for the help ACOMP/2012/094.Candel Bou, JJ.; Jiménez, J.; Franconetti Rodríguez, P.; Amigó Borrás, V. (2014). Effect of laser irradiation on failure mechanism of TiCp reinforcedtitanium composite coating produced by laser cladding. Journal of Materials Processing Technology. 214(11):2325-2332. https://doi.org/10.1016/j.jmatprotec.2014.04.035S232523322141

Reintegration processes of former gang members and former combatants

In a world where conflict is common, effective programs for reintegration of the combatants must exist for the post conflict societies. There is also a growing presence not only of gangs, but also of reintegration programs for those that chose to leave said gangs. To find what parts of those processes are alike and what parts are different is the objective of this thesis. For the former combatants, the thesis focuses on those of the former rebel group, meaning the illegally armed group. The reasons for comparing the two processes are that they outwardly look quite similar in the sense that the both deal with reintegration of formerly armed groups. Both groups have also been involved in some sort of violent action, and they are both being reintegrated into a society that they are not actively full members of. The research is carried out through a desk study using the method of a qualitative research through and abductive approach. The theoretical framework that is used is the inclusion-exclusion framework from the security-development nexus. This is also combined with the use of an analytical framework which was created using three different parts of full reintegration, namely social, political and economical reintegration. Through the usage of the case study of El Salvador, the thesis found that there were both similarities and differences between the two types of reintegration, however, the differences far outweighed the similarities. The thesis also found that while the two processes may be alike from an outside perspective, they are dealing with people of quite different needs. However, some potential can be seen for changes in both processes in order to improve their efficiency, though more research is needed

Control of eta carbide formation in tungsten carbide powders sputter-coated with (Fe/Ni/Cr)

Composite powders of tungsten carbide with variable coating contents of Fe/Ni/Cr based alloys (1-15 wt.%) were prepared by sputtering. The coated powders have revealed a good performance to shape-forming and sintering. However, the presence of nanocrystalline coatings could enhance the formation of a brittle phase during sintering, named [eta]-phase, (M, W)6C. To investigate this effect, the powders were heat-treated at variable temperatures, up to 1400 °C. For comparison, conventionally prepared powders were studied, too, and the content of [eta]-phase was found to be higher for the sputter-coated ones. This result is attributed to the content of binder elements with affinity to carbon, like chromium, enhanced by the difference on binder characteristics, such as nanocrystallinity and morphology. It was concluded that an effective control of the reaction can be achieved by increasing in the binder composition the ratio between the elements without affinity and those with affinity to carbon and/or enlarging the carbon content.http://www.sciencedirect.com/science/article/B6TY1-4MBJY6R-1/1/f383fedbf0fa61a789c1d40bd9608ba