Cubic and hexagonal a-phases, formed during thermal analysis experiments and specific isothermal treatments, have been analyzed for a series of Al-Mn-Si alloys with different iron contents. In these alloys, the Fe/Mn weight ratio was varied from 0.1 to 8.4. This study shows that in Al-Fe-Mn-Si alloys with Fe/Mn weight ratios up to 4, the a-phase has a cubic crystal structure, while in alloys with a Fe/Mn weight ratio of 5.3 or more, the a-phase has a hexagonal crystal structure. Hence, the critical Fe/Mn weight ratio for the cubic to hexagonal crystal structure transition falls between 4 and 5.3 for the studied alloys. KeywordsAluminum alloys; Intermetallic Al-Fe-Mn-Si phases; X-ray analysis diffraction; Crystal structure type.Efecto de la adición de hierro sobre la estructura cristalina de la fase a-AlFeMnSi formada en el sistema cuaternario Al-Fe-Mn-Si ResumenLas fases a de estructura cristalina cúbica y hexagonal, formadas durante los ensayos de análisis térmico y tratamientos isotérmicos específicos, han sido analizadas para una serie de aleaciones Al-Mn-Si con diferente contenido de hierro. En estas aleaciones, la relación en peso Fe/Mn se varió de 0,1 a 8,4. Este estudio muestra que las aleaciones Al-13,4Si-1,1 Mn-Fe con relación en peso Fe/Mn menor o igual a 4, la fase a presenta estructura cristalina cúbica, mientras que en aleaciones con una relación Fe/Mn igual o mayor a 5,3, la fase a presenta estructura cristalina hexagonal. Por lo tanto, la relación crítica Fe/Mn para la transición de estructura cristalina de cúbica a hexagonal se encuentra entre 4 y 5,3 para las aleaciones estudiadas. Palabras claveAleaciones de aluminio; Compuestos intermetálicos Al-Fe-Mn-Si; Difracción de rayos X; Tipo de estructura cristalina.P. OROZCO-gONZálEZ, M. CASTRO-ROMáN, J. lóPEZ-CUEVAS, A. HERNáNDEZ-RODRígUEZ, R. MUñIZ-VAlDEZ, S. lUNA-álVAREZ AND C. ORTIZ-CUEllAR 454 Rev. metal. 47 (6), NOVIEMBRE-DICIEMBRE, 453-461, 2011, ISSN: 0034-8570, eISSN: 1988-4222, doi: 10.3989/revmetalm.1068 1.2, the presence of cubic a and a bcc -AlFeMnSi phases, the latter described as Al 19 Fe 4 MnSi 2 , has been reported [5] . The formation of a hexagonal a h -AlFeMnSi phase, with a formula of Al 8 Fe 2 Si, has also been reported [6, 10 and 11] . Tibballs et al. [12] studied a set of eight alloys of the Al-(6-8)Si-(0.4-3.5)Fe-(0.1-3.6)Mn system. They reported the precipitation of a cubic a c -AlFeMnSi phase in alloys with a Fe/Mn weight ratio up to 8.3, whereas the a h -AlFeMnSi was the stable phase in alloys with a Fe/Mn ratio equal or higher than 12.5.From the point of view of the improvement of the available thermodynamic databases, the study of Al-Fe-Mn-Si system and other alloy systems is gaining importance in basic and applied research. Ravi and Wolverton [13] made a critical comparison of the two commercially available Al-alloy thermodynamic databases: Thermotech and Computherm. They observed some differences in the databases with regard to the intermetallic compounds involving iron, manganese, chromium, and zinc. Thus, they...

No abstract

No abstract

No abstract

Laser welding processes offer significant advantages such as high welding speed, narrow heat affected zone and quality of the welding joint. In this study, the process parameters of laser power and welding speed were modified for AISI 1018 steel plates of 8 mm thickness and compared using finite element method. The results of cross-section microstructure, heat affected zone and fusion zone were characterized. The grain refinement was affected as the parameters were modified. Tensile and microhardness tests were performed to determine the mechanical properties of the welding joints. Microhardness increased in fusion zone and decreased in heat affected zone. Tensile test showed ductile fracture in heat affected zone of the welding joints. The simulated profiles were compared with the experimental observations showing a reasonable agreement.

Este es un artículo publicado en acceso (Open Access) abierto bajo la licencia Creative Commons Attribution NonCommercial, que permite su uso, distribución y reproducción en cualquier medio, sin restricciones siempre que sin fines comerciales y que el trabajo original sea debidamente citado. Resumen: El objetivo de este trabajo fue evaluar el efecto de la profundidad sobre las propiedades en soldaduras de ranura en "V" con varios cordones de relleno. Metal base y electrodos comerciales fueron utilizados (ASTM A36 y AWS E7014) y cuatro diferentes condiciones se utilizaron para desarrollar las soldaduras húmedas como son 10, 20, 30 y 40m de profundidad. Una cámara presurizada con 30 atmósferas de capacidad fue utilizada para simular la profundidad, inundada con agua fresca. Un buzo soldador fue quien realizo las soldaduras. Las propiedades en la sección transversal mediante pruebas de tenacidad CVN (Charpy V-notch), macro ataque y esfuerzo a la tensión fueron determinadas por correlación. Las pruebas mecánicas con mejores resultados se observaron en la condición de 20m de profundidad.Palabras Clave: Soldadura húmeda; Simulación; Microestructura. Weldability Depth Effect of Ferritic Steels in Wet Welding Simulated EnvironmentAbstract: The objective of this work is to evaluate the influence of depth variation on multipass V-groove weld metal properties. Commercial base metal and covered electrodes (ASTM A36 and E7014) and four different conditions were used to perform the wet welds at 10, 20, 30 and 40 m depth. A pressurized chamber with 30 atmospheres capacity filled with water was used to simulate the depth. A certified dive welder was used to perform the welds. The properties in transverse cross-sections, Charpy V-notch tests, macro etching tests and tensile tests were determined for correlation. Mechanical tests showed better properties in the samples extracted from the 20m depth condition.

No abstract

Nucleation of Fe-rich intermetallic phases on α-Al2O3 oxide films was analyzed in five experimental Al-Fe-Mn-Si alloys. In an attempt to verify the role of α-Al2O3 films in nucleating Fe-rich intermetallics, experiments have been conducted under conditions where formed in situ oxide films were present. Some Fe-rich intermetallics are observed to be related with the oxide films in the microstructure, the present results are in accordance with some research that suggest that the Fe-rich intermetallic phases nucleate upon the oxide films. The intermetallic phases and α-Al2O3 films were unambiguously identified with the help of complementary techniques such as thermal analysis, SEM/EDS and X-ray diffraction.