Solid state recycling of Mg-Gd-Y-Zn-Zr alloy chips by isothermal sintering and equal channel angular pressing

The Mg-7Gd-4Y-2Zn-0.5Zr alloy chips were successfully recycled through isothermal sintering and equal channel angular pressing(ECAP).The mechanical properties and microstructure evolution of samples during the recycling process were studied in detail.The eutectic phases in the as-cast alloy transform into long period-stacking ordered(LPSO)phases after homogenization,which can improve the plasticity of the material.After isothermal sintering,the density of the sample is lower than that of the homogenized sample,and oxide films are formed adjacent to the bonding interface of the metal chips.Hence,the plasticity of the sintered sample is poor.Dense samples are fabricated after ECAP.Although the grains are not refined compared to the sintered sample,the microstructure becomes more uniform due to recrystallization.Fiber interdendritic LPSO phase and kinked 14H-LPSO phase are formed in the alloy due to the shear deformation during the ECAP process,which improves the strength and plasticity of the sample significantly.Furthermore,the basal texture is weakened due to the Bc route of the ECAP process,which can increase the Schmid factor of the basal slip system and improve the elongation of the sample.After 2 ECAP passes,the fully densified recycled billet shows superior mechanical properties with an ultimate tensile strength of 307.1 MPa and elongation of 11.1%.

Performance of highly flexible sub-cable for REBCO Cable-In-Conduit conductor at 5.8 T applied field

Due to the high current capability and excellent flexibility,High Flexible REBCO Cables(HFRC)have emerged as an important candidate for composite high‐temperature superconducting conductors.The REBCO six around one Cable‐In‐Conduit Conductor(CICC)concept has been designed for application in the Central Solenoid(CS)coil of the China Fusion Engineering Test Reactor.In the application of fusion devices,the performance of CICC under electromagnetic(EM)loading and thermal stress is very important for reliable and economic operation.Therefore,a 1.22 m long sub‐cable with HFRC design for CICC was manufactured and tested at 4.2 K in a background magnetic field up to 5.8 T.The aim is to investigate the stability of the current‐carrying properties of the HFRC cable under electromagnetic and thermal cyclic loading.The test results show that the critical current(I_(c))of the HFRC cable reached 17.3 kA in a background magnetic field of 5.8 T at 4.2 K.Furthermore,no performance degradation was observed after 24 cycles of 80 kN/m peak load with a background field of 5.8 T and 8 warm‐up‐cool‐down cycles between 77 K and room temperature.The test results provide a good basis for the development of full‐size conductors in future magnet applications.