| Abstrakt: |
The effect of lithium addition on the phase composition, microstructure, and mechanical properties of the Mg-0.5Ni-2Gd-xLi (x = 0, 1, 5, 10, 15, 25 at.%) were investigated. Alloys were cast and subsequently hot extruded at 400 °C with a 16:1 ratio. Microstructure evolution was studied using XRD, SEM with EDX and TEM techniques. An increase in the Li content initially reduced the size and increased the volume fraction of the LPSO phase up to 5 at.% and, further, the volume fraction was reduced. Dual-phase (α-Mg and β-Li) replaced the α-Mg matrix for 15 and 25 at.% Li. The hardness and density of the alloys decreased with Li content. High tensile yield strength of 302 MPa and 5% total elongation was achieved at 5 at.% Li, whereas 25 at.% Li alloys exhibited a low strength (188 MPa) but significant improvement in the total elongation values (37%). The high strength was attributed to the fine grain size of the matrix (2.4 μm) and the uniform dispersion of secondary phases such as LPSO and Mg3Gd. The low strength and high elongation in 25 at.% Li alloy were due to the dual-phase microstructure having a grain size of 8.4 μm and grain boundary secondary phases. [ABSTRACT FROM AUTHOR] |
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