PDF(Pubmed)
Abstract：
High fracture toughness at cryogenic temperature and radiation hardness can be conflicting requirements for the resins for the impregnation of superconducting magnet coils. The fracture toughness of different epoxy-resin systems at room temperature (RT) and at 77 K was measured, and their toughness was compared with that determined for a polyurethane, polycarbonate (PC) and poly(methyl methacrylate) (PMMA). Among the epoxy resins tested in this study, the MY750 system has the highest 77 K fracture toughness of KIC = 4.6 MPa√m, which is comparable to the KIC of PMMA, which also exhibits linear elastic behaviour and unstable crack propagation. The polyurethane system tested has a much higher 77 K toughness than the epoxy resins, approaching the toughness of PC, which is known as one of the toughest polymer materials. CTD101K is the least performing in terms of fracture toughness. Despite this, it is used for the impregnation of large Nb3Sn coils for its good processing capabilities and relatively high radiation resistance. In this study, the fracture toughness of CTD101K was improved by adding the polyglycol flexibiliser Araldite DY040 as a fourth component. The different epoxy-resin systems were exposed to proton and gamma doses up to 38 MGy, and it was found that adding the DY040 flexibiliser to the CTD101K system did not significantly change the irradiation-induced ageing behaviour. The viscosity evolution of the uncured resin mix is not significantly changed when adding the DY040 flexibiliser, and at the processing temperature of 60 °C, the viscosity remains below 200 cP for more than 24 h. Therefore, the new resin referred to as POLAB Mix is now used for the impregnation of superconducting magnet coils.
摘要：
低温下的高断裂韧性和辐射硬度可能是对用于浸渍超导磁体线圈的树脂的矛盾要求。测量了不同环氧树脂体系在室温（RT）和77K下的断裂韧性，并将它们的韧性与聚氨酯的韧性进行了比较，聚碳酸酯（PC）和聚（甲基丙烯酸甲酯）（PMMA）。在这项研究中测试的环氧树脂中，MY750系统具有最高的77K断裂韧性KIC=4.6MPa√m，与PMMA的KIC相当，这也表现出线性弹性行为和不稳定的裂纹扩展。测试的聚氨酯体系具有比环氧树脂高得多的77K韧性，接近PC的韧性，它被称为最坚韧的聚合物材料之一。CTD101K在断裂韧性方面表现最差。尽管如此,由于其良好的加工能力和相对较高的抗辐射能力，用于大型Nb3Sn线圈的浸渍。在这项研究中,CTD101K的断裂韧性通过添加聚乙二醇增韧剂AralditeDY040作为第四组分而得到改善。不同的环氧树脂体系暴露于质子和γ剂量高达38MGy，发现将DY040增韧剂添加到CTD101K系统中不会显着改变辐照引起的老化行为。添加DY040增韧剂时，未固化树脂混合物的粘度变化没有显著变化，在60°C的加工温度下，粘度保持在200cP以下超过24小时。因此，称为POLABMix的新树脂现在用于浸渍超导磁体线圈。
