张昌盛马天宇严密裴永茂高旭
金属学报
采用区熔定向凝固方法, 以480 mm/h速度制备了<110>取向Tb0.36Dy0.64(Fe0.85Co0.15)2合金棒. 通过测试在0---0.325 T磁场范围内合金 棒的应力--应变回线, 计算了应力幅σm分别为-10,-30和-50 MPa的阻尼系数Δ W/W. 结果表明, 零磁场下的Δ W/W最大; 随磁场强度增大, 同一σm条件下的Δ W/W逐渐降低. 在低磁场中, Δ W/W随σm的增加而降低; 在高磁场中, Δ W/W随σm的增加而升高. 利用不同预压应力下的磁致伸缩--磁化强度关系曲线, 分析了磁场--应力复合加载条件下非180°磁畴和畴壁的运动形式. 依据局部内应力理论, 解释了合金棒的磁机械阻尼系数随外磁场强度和应力幅值变化的规律.
关键词:
Tb--Dy--Fe合金
,
magnetostriction
,
magnetomechanical damping
,
magnetization
TANG Hong
,
XIANYU Ze
,
HU Qianli
,
QIAO Guiwen
,
WANG Yongzhong
,
ZHUANG Yuzhi1 1) Institute of Metal Research
,
Chinese Academy of Sciences
,
Shenyang
,
China 2) Northeastern University
,
Shenyang
,
China Manuscript Received 7 March 1995
金属学报(英文版)
In this study, high-Tc YBaCuO superconductors with high Jc value were prepared using MTG(melting-textured growth) method. These superconductors with high density have Jc value in excess of 1.6×104 A/cm2 (77K, zero field) determined by using a d.c. standard four terminal method with the criterion of lμV/cm. The XRD and fractograph analysis revealed that the texture existed in whole MTG-processed YBaCuO sample which consists of the layered and plate-like grains of matrix phase YBa2Cu3Oy unidirectionally aligned along its (103) planes. The experimental results indicated that the connectivity between superconducting grains has been improved greatly and the weak-link problem has been overcome essentially.
关键词:
: YBaCuO high-Tc superconductor
,
null
,
null
,
null
