高场磁体用RRP Nb3Sn股线的研制

采用Rod Restack Process(RRP)研制了单根线长大于1500m的高场磁体用Nb3Sn股线,股线选用Nb作为扩散阻隔层,分布于各亚组元周围。在热处理时Nb阻隔层不但可以阻止Sn向稳定体Cu区的扩散,防止稳定体的Sn扩散污染,确保股线具有较高的剩余电阻率(RRR),同时,靠近Sn源内侧的Nb参与固态扩散反应生成A15相Nb3Sn,贡献临界电流。在股线的制备过程中,采用Nb-47%Ti(质量分数)芯代替部分Nb芯的方式添加元素Ti,达到了Ti元素添加目的,该方法因为使用了已经商业化的Nb-47%Ti而有效控制了制作成本。对该股线进行热处理以及超导性能测试研究表明:640℃,60h热处理条件下,股线在12T,4.2K,0.1μV/cm下的Ic为514A,股线的RRR为148,具有良好的绝热稳定性;在650℃,100h下股线的Ic为599A,RRR=3.77。股线扩散阻隔层以及添Ti方式的成功选择,为获得长线打下了基础,为股线性能的初步研究及后续的实验提供了直接参考。     

Fe60CoxZr10Mo5W2B23-x(x=1,3,5,7,9)块状金属玻璃的非晶形成能力

The bulk Fe60CoxZr10Mo5W2B23-x (x= 1, 3, 5, 7, 9) amorphous rods with diameters of1.5 mm were successfully prepared by copper mold casting method with the low purity raw materials.The amorphous and crystalline states, and thermal parameters, such as the glass transition temperature (Tg), the initial crystallization temperature (Tx), the supercooled liquid region (ΔTx = TxTg), the reduced glass transition temperature Trg (Tg/Tm, Tm: the onset temperature of melting of the alloy, and Tg/T1, T1 : the finished temperature of melting of the alloy) were investigated by X-ray diffractometry (XRD) and differential scanning calorimetry (DSC) analysis. Glass forming ability of Fe60CoxZr10Mo5W2B23-x (x=1, 3, 5, 7, 9)bulk metallic glasses has been studied. According to the results, the alloy (x=7) with the highest Trg (Tg/T1 =0. 607, Tg/T1 =0.590) value, has the strongest glass forming ability among these alloys because its composition is near eutectic composition.The wide supercooled liquid region over 72 K indicates the high thermal stability for this alloy system.This bulk metallic glass exhibits quite high strength (Hv 1020). The success of production of the Febased bulk metallic glass with industrial materials is of great significance for the future progress of basic research and practical application.