Superconducting round wires with isotropic architecture are preferred in fabrications of cables and magnets. To diminish the obstacles to supercurrent, e.g., voids, cracks and bubbles, over-pressure heat treatment or hot isostatic pressing is indispensable in the final annealing process. Here, we fabricated a stainless steel/Cu/Ag sheathed Ba_0.6K_0.4Fe₂As₂ superconducting round wire without the aid of high-pressure sintering. It was found that high-strength outer sheaths and groove rolling synergistically enhance the core density to ∼100%. Combined with the fiber and concentric texture of the superconducting core, the J _c reaches 4.45 × 10⁴ A cm⁻² at 4.2 K and 10 T. Furthermore, the specially designed conductor architecture not only reduces material costs by lowering the proportion of Ag to ∼3.1%, but also provides high mechanical and thermal stability. This straightforward and cost-effective process can be scaled up for the massive production of long wires for high-field applications.

中文翻译：

---

环境压力退火的低成本铁基超导圆线的高临界电流密度

具有各向同性结构的超导圆线是电缆和磁体制造中的首选。为了减少超电流的障碍，例如，空洞、裂纹和气泡，在最终退火过程中不可缺少过压热处理或热等静压。在这里，我们在没有高压烧结的情况下制造了不锈钢/Cu/Ag护套Ba _0.6 K _0.4 Fe ₂ As _{2超导圆线。}研究发现，高强度外护套和滚槽可协同将芯密度提高至约 100%。结合超导芯的纤维和同心织构，J _c在4.2 K和10 T下达到4.45 × 10 ⁴ A cm ^-2。此外，专门设计的导体结构不仅通过将Ag的比例降低至∼3.1%来降低材料成本，而且还提供了高机械稳定性和热稳定性。这种简单且经济高效的工艺可以扩大规模，用于高场应用的长线的大规模生产。