Papers by Ireri Aydee Sustaita Torres
Se estudió la evolución microestructural en dos aleaciones resistentes al calor envejecidas a 750... more Se estudió la evolución microestructural en dos aleaciones resistentes al calor envejecidas a 750°C por periodos de hasta 1000 h mediante microscopía óptica y electrónica de barrido. La transformación de NbC a Nb 3 Ni 2 Si se describe por medio de la técnica de electrones retrodispersados, así como análisis de la espectrometría de rayos X en el microscopio electrónico de barrido. La microstructura de las aleaciones en su condición de vaciado consiste en una matriz de austenita con una red de carburos primarios de los tipos NbC y M 7 C 3 . El envejecimiento promueve la precipitación de carburos secundarios M 23 C 6 y la transformación de NbC a Nb 3 Ni 2 Si. Los resultados muestran que esta última transformación se inicia en los límites del carburo hacia su centro, enriqueciéndolo con silicio y níquel, a la vez que el carbono migra a la matriz promoviendo la precipitación de carburos ricos en cromo. Aleaciones resistentes al calor, envejecimiento, evolución microestructural.
Aging of Cast Heat Resisting Alloys 35Cr–45Ni–0.1C (MORE40X) and 40Cr–45Ni–0.2C (UCX)
Springer eBooks, 2015
Heat resisting cast alloys are designed to sustain operation while are exposed to temperatures gr... more Heat resisting cast alloys are designed to sustain operation while are exposed to temperatures greater than 650 °C. These alloys have widespread uses in petrochemical industry in pyrolysis and reformer furnaces, etc.; in addition, they can be hold into oxidizing, sulfidizing, or carburizing environments. The principal attributes of the alloys are creep strength and corrosion resistance. The purpose of this study was to explore the effects of chromium contents in two centrifugal cast pipes of Ni-base heat resistant alloys, one MORE40X 0.1C and the other UCX 0.2C during aging. The behavior of this alloys during aging was examined by optical and scanning electron microscopy in samples aged at 750 °C up to 1,000 h. The microstructural evolution was analyzed on selected samples and images using secondary and backscattered electron detectors and with X-ray energy dispersive spectroscopy. The main microstructural changes in primary and secondary carbides that occurred during aging were described and related to mechanical properties in two alloys. The microstructure as cast materials shows a primary carbides network, in austenitic matrix. The aging times produced different changes in the alloys, which dependent of the composition, morphology, distribution and in the transformation of carbides inside them. It was found that aging promoted the increment in tensile strength and the reduction in ductility. However the mechanical properties of UCX (aged at 750 °C up to 1,000 h) are better with respect to MORE40X (as cast).
Envejecimiento de aleaciones resistentes al calor 35Cr-45Ni alto y bajo carbono
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Papers by Ireri Aydee Sustaita Torres