Tribological Properties of Magnet Structural Materials at Cryogenic Temperatures

低温下磁体结构材料的摩擦学性能

• 批准号: 02650106
• 负责人: IWABUCHI Akira
• 金额: $ 1.28万
• 依托单位: Iwate University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1990
• 资助国家: 日本
• 起止时间: 1990 至 1991
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02650106/
• 关键词: Cryogenic Temperature; Superconducting Magnet; Frictional Heating; Tribology; Quench; Temperature Rise; Magnet Structural Materials; Cryogenic Vacuum; 機械的じょう乱; クライオメカニックス

In this project tribological properties of magnet structural materials were investigated at cryogenic temperatures, because frictional heating due to sliding in a magnet caused the quench of it.(1)Frictional heatingIn the friction test at cryogenic temperature in liquid helium, temperature rise was measured by two thermocouples inserted into a specimen. Frictional heating appeared as a pulse with sharp fluctuation. Temperature rise was increased with frictional heat, but the relationship between them was not linear. This meant that not all the frictional heat generated but the some fraction of it contributed to the temperature rise of the specimen because of the cooling by liquid helium.Numerical simulation was carried out by using the experimental data of temperature rise. The simulation dealt with the inverse problem of unsteady heat conduction. From this simulation the temperature distribution of the specimen was obtained, where the temperature decreased steeply with depth from the … More interface of the specimen. Furthermore, the integrated heat flux showed the heat contributing to the temperature rise was less than 50 % of the frictional heat generated during sliding.(2)Friction test in vacuum at cryogenic temperatureA superconducting magnet is set in a vacuum vessel, and therefore, friction problem occurs in vacuum at cryogenic temperature. The experimental apparatus was constructed for the friction test in this environment, and friction tests were carried out for 24 combinations of specimen. In the cases such as JN2-JN2 the coefficient of friction was low at 5 K, but quite high at 77 K due to the adhesion between surfaces. On the other hand, in the case of JN2-CuNi the coefficient of friction was high at 4 K. These properties were dependent on hardness of materials. The hardness increased with decreasing temperature, and the adhesion was prevented above a certain value of the hardness. Temperature dependence of hardness was also obtained, where coefficient of friction increased between 20 to 50 K, and decreased between 80 to 110 K for JN2-Cu. Less

在这个项目中，研究了磁铁结构材料在低温下的摩擦学性能，因为磁铁滑动引起的摩擦加热导致了它的淬火。(1)摩擦加热在液氦低温下的摩擦试验中，通过在试样中插入两个热电偶来测量温升。摩擦加热表现为具有剧烈波动的脉冲。温升随摩擦热的增加而增加，但两者之间不是线性关系。这意味着并不是所有产生的摩擦热，而是其中的一部分由于液氦的冷却而使试样的温度升高。利用温升实验数据进行了数值模拟。模拟处理了非定常热传导的反问题。通过模拟得到了试样的温度分布，其中温度随试样接触界面深度的增加而急剧下降。此外，综合热流密度表明，导致温度上升的热量小于滑动过程中产生的摩擦热量的50%。(2)低温下真空摩擦试验由于超导磁体设置在真空容器中，因此在低温下真空中会出现摩擦问题。搭建了该环境下的摩擦试验装置，进行了24组试件的摩擦试验。在JN2-JN2等情况下，摩擦系数在5k时很低，但在77k时由于表面之间的粘附而相当高。另一方面，在JN2-CuNi的情况下，在4 K时摩擦系数很高。这些特性取决于材料的硬度。硬度随温度的降低而升高，超过一定的硬度后，粘接现象被阻止。硬度随温度变化，摩擦系数在20 ~ 50 K之间增大，在80 ~ 110 K之间减小。少

项目成果

A. IWABUCHI, and K. KOMURO: "Frictional heating of magnet structural materials at cryogenic temperatures" Cryogenics. 31. 969-974 (1991)

A. IWABUCHI 和 K. KOMURO：“低温下磁体结构材料的摩擦加热”Cryogenics。

岩渕 明: "4KにおけるJN1,JN2と銅及び銅合金のフレッティング状態下における摩擦特性"

Akira Iwabuchi：“JN1、JN2、铜和铜合金在 4K 微动条件下的摩擦性能”

A.IWABUCHI: "Frictional Heating of Magnet Structural Materials at Cryoqenic Temperatures" Cryoqenics.

A.IWABUCHI：“低温下磁体结构材料的摩擦加热”低温学。