Fabricación y Caracterización de Aleaciones WC-Co-Cr con WC Nanométricos y Bimodales por Molienda Mecánica
Cermets or composite materials are composed of ceramic and metal materials. The metal acts as a binder to protect the brittleness of the ceramic which provide resistance. Tungsten carbide (WC) is the most commonly used cermet in a wide range of industrial applications due to its high hardness, tough...
| Autores: | , , |
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| Tipo de recurso: | tesis de maestría |
| Estado: | Versión publicada |
| Fecha de publicación: | 2018 |
| País: | México |
| Institución: | Universidad Autónoma de Zacatecas |
| Repositorio: | Repositorio Institucional Caxcán |
| Idioma: | español |
| OAI Identifier: | oai:http://ricaxcan.uaz.edu.mx:20.500.11845/1992 |
| Acceso en línea: | http://ricaxcan.uaz.edu.mx/jspui/handle/20.500.11845/1992 |
| Access Level: | acceso abierto |
| Palabra clave: | INGENIERIA Y TECNOLOGIA [7] WC-Co-Cr Molienda mecánica Tamaño de WC |
| Sumario: | Cermets or composite materials are composed of ceramic and metal materials. The metal acts as a binder to protect the brittleness of the ceramic which provide resistance. Tungsten carbide (WC) is the most commonly used cermet in a wide range of industrial applications due to its high hardness, toughness, and wear resistance (including sliding, abrasion and erosion). The development and study of this material at nanometric level has resulted from the rapid technological progress and the need on further improving their properties. Materials with nanometric grain size have shown enhanced performance compared to conventional materials with micrometric grain size. Mechanical milling is a versatile technique for processing these materials with different grain size. In the present study, four WC-Co-Cr alloys were prepared by mechanical milling, namely as: nano66, nano86, bimo66, and bimo86 with different WC size, nanometric and bimodal, and binder phase percentage (Co and Cr). The prefix nano indicates that the alloy is composed of nano-sized WC powders while bimo stands for a mixture of sub-micron (60%) and micrometric (40%) WC. The numbers 66 and 86 indicate the content of WC (in wt. %) in the alloy while the rest belongs to the binder-cobalt-chromium phase. The effect of the ball milling diameter and milling time was analyzed during the processing of the alloys with nanometric WC. After the sub-micrometric size was obtained, the WC particles were milled with Co and Cr. The microstructural characterization shows that sub-micrometric WC sizes were reached after 40 minutes of milling using balls of different size. Transmission electron microscopy corroborates in the sub-micrometric size of the WC. No additional phases were detected by XRD patterns of the milled alloys; however, the peaks of the nanosized WC crystals present a broadening as a result of crystal refinement and to the increase of microstrains of the powder particles. The results of differential scanning calorimetry DCS show that the bimo alloys have a higher transformation temperature than the nano alloys with 1340 and 1294 ° C respectively, which can directly affect the microstructure and properties when subjected to consolidation processes that handle temperatures similar to those mentioned. |
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