Metals and Materials International ( IF 3.3 ) Pub Date : 2021-09-02 , DOI: 10.1007/s12540-021-01023-5 Young-Seok Oh 1, 2 , Jeong Whan Yoon 1 , Ho Won Lee 2 , Seong-Hoon Kang 2 , Kook-Chae Chung 3 , Duck-Young Hwang 4
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Numerical modeling was conducted to investigate the deformation behavior of powder mixture during multi-pass drawing processes for multi-filamentary MgB2 wire. A modified Drucker-Prager Cap (DPC) model with an elliptical cap surface using the new material characterization method was developed to capture the anisotropic hardening behavior and hydrostatic effect of the powder mixture. A number of uniaxial die compaction, cold isostatic pressing, diametrical compression, and uniaxial compression tests were conducted using different powder densities to characterize the modified DPC model. A commercial finite element software ABAQUS with a user subroutine was used to simulate the drawing of the MgB2 wire. The density and area fraction of the powder mixture during the wire-drawing process were verified with experimental results. The difference in packing density at the inner and outer filaments of the MgB2 wire was successfully captured by simulation. In addition, the effect of the initial packing density on the superconducting properties of MgB2 wire was numerically studied. It is shown that the increase in the superconducting area, which results from a high initial packing density, should be more effective compared to the increase in the grain connectivity in enhancing the critical current properties for the MgB2 wire when the final packing density is saturated after a number of drawing processes.
Graphic abstract
中文翻译：
考虑各向异性硬化行为和静水效应的超导 MgB2 拉丝
进行数值模拟以研究粉末混合物在多丝 MgB 2线的多道次拉拔过程中的变形行为。改进的 Drucker-Prager Cap (DPC) 模型具有使用新材料表征方法的椭圆形帽表面，用于捕捉粉末混合物的各向异性硬化行为和流体静力学效应。使用不同的粉末密度进行了许多单轴模具压实、冷等静压、径向压缩和单轴压缩测试，以表征修改后的 DPC 模型。带有用户子程序的商用有限元软件 ABAQUS 用于模拟 MgB 2的绘制金属丝。通过实验结果验证了拉丝过程中粉末混合物的密度和面积分数。通过模拟成功捕获了 MgB 2线的内部和外部细丝的填充密度差异。此外，数值研究了初始填充密度对MgB 2线材超导性能的影响。结果表明，当最终填充密度饱和时，与晶粒连通性的增加相比，由高初始填充密度导致的超导面积的增加应该更有效地增强 MgB 2线的临界电流特性经过一系列的绘图过程。
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