Effect Of Gd Addition Research Articles

Effects of addition of rare earth element Gd on the lamellar grain sizes of a binary Ti-44Al alloy

Effect of Gd addition on microstructure, martensitic transformation and strain recovery characteristics was investigated. Gd addition resulted in the significant reduction of grain size and formation of Gd-rich phase. The Gd-rich phase was identified as Gd3(Ti,V) phase with an orthorhombic structure. The solution treated (Ti-13V-3Al)100−xGdx alloys underwent a α″ → β transformation during heating, irrespective of Gd content. But Gd addition led to a slight drop of martensitic transformation temperatures. In addition, the moderate Gd addition can promote the achievement of outstanding mechanical and functional properties due to the combination of the grain refinement and precipitation strengthening of Gd-rich phase in grain interior. Ti-V-Al alloy with an optimal Gd content, which was Ti-V-Al alloy containing 0.3 at.% Gd, showed the largest recoverable strain of 4.9% at a pre-strain of 6% and the ultimate tensile stress of 925 MPa. Meanwhile, Ti-V-Al alloy had a superior elongation of 20.7%, as 0.3 at.% Gd was added.

Effect of Gd addition on the superconducting properties of (Nd-Sm-Eu)123 system

Bulk (Nd, Sm, Eu)1-xGdxBa2Cu3 Oy superconductors in which the Gd content x ranged from 0 to 0.25, were grown by the oxygen-controlled-melt-growth (OCMG) method. X-ray diffraction results show that the main phase is RE123 with a small amount of the second phase. SQUID measurements on the oxygenated samples showed that a small amount of Gd123 addition to (Nd, Sm, Eu)123 increased Tc and made the superconducting transition sharper. All the samples, except the Gd-free one, exhibited the secondary peak effect in the magnetization curves, which shows that the field-induced pinning is active, like the other RE123 fabricated by the OCMG process. The critical current density also increased with Gd addition, however, no systematic change was observed with the amount of Gd addition. A peak Jc value of 60,000 A/cm2 was recorded with an applied field of 1.2 T (H//c) at 77 K. The results suggest that, in the (Nd, Sm, Eu)123 system the addition of Gd is effective in achieving high Tc and a large Jc.