Abstract
Tres aleaciones Mg-Gd ensayadas a compresión a temperaturas intermedias muestran un fenómeno de serrado dependiente de la velocidad de deformación y de la temperatura de ensayo. La aparición de este fenómeno se relaciona con la segregación de átomos de soluto en las dislocaciones móviles y/o en las fronteras de macla. Los ensayos de compresión se han realizado en un intervalo de temperaturas comprendido entre 25 y 300 °C y a velocidades de deformación comprendidas entre 4×10−5 y 8×10−3 s−1 con el fin de analizar el fenómeno de serrado, e implícitamente, el proceso de envejecimiento dinámico por deformación. Experimentalmente se ha comprobado que el aumento de la concentración de gadolinio en solución sólida disminuye la energía de activación del proceso.
Highlights
A wide variety of materials are used in applications in which resistance to mechanical loading is necessary
Rare Earth (RE) elements added in solid solution in magnesium alloys have a great impact in their mechanical properties which make them perfect candidates for structural applications in the automotive and aerospace industry
The increase in the gadolinium content in solid solution increases the lattice parameters, a and c, in agreement with previous results (Xu et al, 2017). {10 ̄10} and (0002) pole figures shows that the alloy shows a fiber texture with the basal plane parallel to the extrusion direction
Summary
A wide variety of materials are used in applications in which resistance to mechanical loading is necessary. It was demonstrated in previous studies that the addition of RE elements in Mg enhances its formability and creep resistance (Ball and Prangnell, 1994; He et al, 2007; Stanford et al, 2008; Zhu et al, 2010; Hantzsche et al, 2010; Yuan et al, 2013; Gravas et al, 2016; Griffiths, 2015; Wang et al, 2015) Due to their bigger atomic radius compared to the magnesium atomic radius, RE atoms trigger distortions in the crystalline magnesium lattice that lead them to interact with dislocations, twins and grain boundaries. The present article studies DSA phenomenon in extruded Mg-1%Gd, Mg-3%Gd and Mg6%Gd alloys under compressive testing at temperatures between 25 °C and 300 °C in a wide range of strain rates. The critical strain for DSA will be analyzed to calculate the activation energy This is part of a deep study of the influence of the segregation of gadolinium atoms in dislocations and twins and its influence in the mechanical strength. The grain size was measured by the linear intercept method from at least 4 different images
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