叠片结构对铜抗热疲劳性能的影响研究

Thermal Fatigue Resistance Enhancement of Laminated Copper Foil

研究了一种多层铜箔构成的叠片式表面结构,与铜块体同时在10-5Pa真空下进行电子束热疲劳,电子束的功率密度28 MW/m^2,循环3000次。采用扫描电子显微镜(SEM)对热疲劳后的铜箔与铜块体的表面损伤进行了分析,结果表明,由于铜箔处于单轴应力状态,表面产生的热应力较小,导致表面裂纹较细较少,且多产生垂直于箔片方向的裂纹,难以扩展。结合SEM照片,利用计算机图片处理软件,对叠片结构的铜箔与铜块体表面裂纹损伤进行了定量分析。结果表明,叠片结构的铜箔表面的裂纹密度和宽度均远小于铜块体,表现出更好的抗热疲劳开裂性能。而且,铜箔的厚度越小其抗热疲劳开裂性能越优异。该思路将为解决面向等离子体、非晶甩带冷却辊等材料的热疲劳问题提供有益参考。

Herein, we experimentally addressed the thermal fatigue resistance enhancement of laminated copper foil. The influence of the experimental conditions, including the e-beam power density and foil thickness, on the formation of surface cracks was quantitatively investigated with scanning electron microscope and computer image processing. The results show that depending on the foil thickness, the laminated copper foil displayed much stronger thermal fatigue resistance than bulk copper. For example, the cracks on folded-end surfaces of copper foil were much fewer, narrower, shorter and more difficult to propagate on the surfaces than those on bulk copper, possibly because of uniaxial stress state and less thermal stress; and a decrease of foil thickness considerably increased the thermal fatigue resistance. We suggest that the laminated copper foil may he good plasma facing and amorphous-ribbon cooling-roll materials.