Microstructural evolution and mechanical properties of Mg-5Y-5Gd-xNd-0.5Zr magnesium alloys at different states

Abstract

The microstructural evolution and mechanical properties of Mg-5Y-5Gd-xNd-0.5Zr magnesium alloys at different states were studied. The results reveal that island compounds at the grain boundaries of the as-cast alloys mainly were Mg 24 Y 5 , Mg 41 Nd 5 , and Mg 5 Gd phases. After homogenization at 808 K for 24 h, the distribution of the island compounds became discrete and Mg 5 Gd phases mostly decomposed and dissolved. With hot extrusion, the grain size was refined to about 20 μm on average, and both the strength and elongation were greatly improved. After ageing at 523 K for 5 h, the strength of different extruded alloys largely increased but the elongation decreased. With the increase of neodymium content, the strength of the alloys at different states increased. The content of neodymium element had an obvious effect on the elongation of the designed alloys. In the designed alloys, the Mg-5Y-5Gd-2.2Nd-0.5Zr alloy exhibited the best combination properties and its ultimate tensile strength, yield strength, and elongation could reach 380 MPa, 285 MPa, and 9.0%, respectively.

Investigation of Mechanical Properties and Microstructure of Non-Commercial Magnesium Alloy Prepared by Extrusion and ECAP

“…In the Ex condition, higher values of YCS measured in the Y direction resulted from the stripe-like formation of the secondary phase particles. As shown in a previous report, texture present in the as-extruded condition did not lead to any difference in YCS measured along both measured directions [9]. ECAP processing resulted in the disruption of these stripes; therefore, no difference should have been observed anymore.…”

“…As mentioned above, annealing of the investigated material prior to the extrusion did not lead to complete dissolution of all secondary phase particles. As a result, extrusion led to formation of typical stripes of particles aligned along the extrusion direction [9], see Fig. 2a.…”

The relationship between microstructure and corrosion behaviors of Mg‐3Y‐xNd alloys (x = 0.5, 1.0, 1.5 wt%)

“…With the increasing of Nd‐content, the eutectic precipitated phase Mg 14 Y 2 Nd increased to form the continuous uniform distribution. The contents of Y and Nd elements in precipitated phases were rich due to the solute atoms enriching in the solid/liquid interface during non‐equilibrium solidification .…”

Study on Processing Technique in Engineering Tests of Mg-7.1Gd-4.6Y-1.3Nd-0.5Zr Alloy

“…During ingot cogging down, one hand to ensure adequate deformation of the ingot while required the deformation full deep into center part of ingot. On the other hand, the slip of polycrystalline magnesium alloy was less that the grain was not easy to generate macroscopic yield and produce a lot of stress concentration at grain boundaries [6][7][8] . Therefore, forging process was very easy to cause uneven deformation and caused ingot cracking for stress concentration.…”