Suchergebnisse

Apresentação do Dossiê "Afetividades marginais, grupos armados e mercados ilegais" feita pelos organizadores.

Mode of access: Internet. ; Sign.: ¶-2¶4,¶-3¶4, 4¶2, A-S4, T2, V-Z4, 2A-2E4, 2F2.

La tesis principal que sostenemos en este capítulo es que las nuevas tecnologías de la información y la comunicación (NTIC) responden al contexto socio-histórico y a los intereses de quienes las crearon, administran y toman las decisiones sobre su uso. Es decir, ellas por sí solas no son necesariamente ni buenas ni malas.

46 56 135 ; S ; [EN] In this work, a novel amorphous-nanocrystalline titanium-niobium-manganese solid solution ternary alloy with a Ti-33Nb-4Mn (at.%) nominal composition was developed by a High-Energy Mechanical Alloying. Nb and Mn were added to the elemental Ti as a beta-phase (bcc) stabilizer and an amorphization promoter, respectively. The system evolved from the elemental Ti, Nb and Mn raw materials to a body centred cubic (bcc) TiNbMn alloy and, finally, to the formation of an original and stable face centred cubic (fcc) nanocrystalline TiNbMn alloy, not reported until now, at short milling time (20 h). This alloy remains invariant until 120 h. In turn, the partial amorphization of the system occurs and increases until at intermediate milling time (80 h). The production of both original fcc and the amorphous TiNbMn alloy may be beneficial for reducing the Young's modulus and improving the mechanical strength pursued for the Ti alloy. The optimal milling time respect to the amorphization, nanocrystalline size and Fe mount from milling media was 60 h and 80 h (TiNbMn60h and TiNbMn80h), with > 50 wt% of an amorphous phase and a crystalline domain size of approximately 5 nm. This work was supported under postdoctoral grant no. 3150060, which is financed by the FONDECYT fund (Government of Chile). Chicardi, E.; García-Garrido, C.; Sayagués, M.; Torres, Y.; Amigó, V.; Aguilar, C. (2018). Development of a novel fcc structure for an amorphous-nanocrystalline Ti-33Nb-4Mn (at.%) ternary alloy. Materials Characterization. 135:46-56. https://doi.org/10.1016/j.matchar.2017.11.021