This study evaluates the thermal expansion coefficient, as well as the elastic-, plastic- and fracture behaviour, at ambient and cryogenic (liquid nitrogen) temperatures, of four different epoxy systems that are used in high-field superconducting magnets, with the emphasis on rate-dependent plasticity as measured by uniaxial compression testing. As expected, both the elastic and plastic behaviour of the epoxy systems at room temperature depend strongly on their distance to the glass transition temperature, but become similar at cryogenic temperature. The rate dependency of the yield stress at room temperature of the four epoxy systems was similar and is well described by the Eyring model. At cryogenic temperatures the rate dependency disappears and the yield stress of all four epoxy systems approach a similar athermal value. The fracture toughness remained equal or even increased upon cooling to cryogenic temperatures for each of the four epoxies. However, the fracture toughness values of the four epoxies tested were quite different from each other, suggesting that fracture toughness not only depends on the van der Waals interactions between the segments but is also determined by other molecular characteristics, such as the network structure.

这项研究评估了在高场超导磁体中使用的四种不同的环氧体系在环境温度和低温（液氮）温度下的热膨胀系数以及弹性，塑性和断裂行为。通过单轴压缩测试测得的与速率相关的可塑性。如预期的那样，环氧树脂体系在室温下的弹性和塑性行为都很大程度上取决于它们与玻璃化转变温度的距离，但在低温下却变得相似。四种环氧体系在室温下的屈服应力与速率的关系是相似的，并且由Eyring模型很好地描述了。在低温下，速率依赖性消失，所有四个环氧体系的屈服应力接近相似的无热值。对于四种环氧树脂中的每一种，当冷却至低温时，断裂韧性保持相等或什至增加。但是，所测试的四种环氧树脂的断裂韧性值彼此完全不同，这表明断裂韧性不仅取决于链段之间的范德华相互作用，而且还取决于其他分子特性，例如网络结构。