DEVELOPMENT OF CRYOGENIC HARDINESS TESTER AND FRICTION TESTER AT CRYOGENIC TEMPERATURE

低温硬度计和低温摩擦试验机的研制

• 批准号: 11555048
• 负责人: IWABUCHI Akira
• 金额: $ 8.64万
• 依托单位: IWATE UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11555048/
• 关键词: HARDNESS; HARDNESS TESTER; CRYOGENIC TEMPERATURE; GM-REFRIGERATOR; SUPERCONDUCTORS; FRICTION TESTER; TEMPERATURE DEPENDENCE; FRACTURE TOUGHNESS; トライボロジー; ビッカース硬さ

In this work we developed the new Vickers-type cryogenic hardness tester, using GM-refrigerator. The old one was cooled with liquid helium, but the temperature and temperature rising rate could not be controlled because of the evaporation of liquid helium. Therefore, we introduced a GM-refrigerator to control in a vacuum chamber. The performance of the hardness tester was acceptable. The problem was not to cool a specimen at around 4 K due to the contact resistance of conduction from the second cooling stage head of the refrigerator and the specimen. The temperature was cooled down at around 30 K in this tester.We measured the hardness not only metallic specimens such as SUS316L stainless steel, but also high temperature superconductors such as YBCO, and ((Nd,Eu,Gd)BaCuO). The latter was used as the bulk magnet, but it breaks down easily with Lorentz force during magnetizing. The fracture toughness K_<IC> was evaluated from the hardness and the crack size initiated from an indented scar during hardness test. Generally, hardness was increased with decreasing temperature monotonically with rather great scatter, but the fracture toughness was slightly decreased with temperature. For example, the hardness of (Nd,Eu,Gd)BaCuO was 9,800 MPa at 40 K. The fracture toughness depends on the crystal plane because there were many inherent cracks on the (100) plane and it was easier for cracks to propagate.We also equipped the pin-on-desk type friction tester with a reciprocating sliding motion in the chamber. The temperature of the specimen was valid from 40 K to room temperature. Unfortunately, we could not obtain the frictional date due to lack of time. The performance of the frictional tester was examined at 40 K and room temperature, and we are satisfied. Later, we will obtain the temperature dependence of coefficient of friction of materials.

本工作采用GM制冷机，研制了新型的维氏低温硬度计。旧的用液氦冷却，但由于液氦的蒸发，温度和升温速率无法控制。因此，我们引入了一个GM制冷机在真空室中进行控制。硬度计的性能是可接受的。问题在于，由于制冷机的第二冷却台头和试样的传导的接触电阻，不能在4K左右冷却试样。在该试验机中冷却至30 K左右，不仅测定了SUS316 L不锈钢等金属试样的硬度，还测定了YBCO、（（Nd，Eu，Gd）BaCuO）等高温超导体的硬度。后者被用作块体磁体，但在磁化过程中容易被洛伦兹力击穿。断裂韧性K_<IC>由硬度和硬度试验中压痕处裂纹的尺寸来评价。硬度随温度的降低而单调增加，但分散性较大，断裂韧性随温度的升高略有降低。例如，（Nd，Eu，Gd）BaCuO的硬度在40K下为9，800MPa。断裂韧性取决于晶面，因为（100）面上有许多固有裂纹，裂纹更容易扩展。我们还配备了在室内往复滑动的销台式摩擦试验机。样品的温度从40 K到室温都是有效的。不幸的是，由于时间不够，我们无法获得摩擦日期。在40 K和室温下对摩擦试验机的性能进行了测试，结果令人满意。随后，我们将得到材料摩擦系数的温度依赖性。

项目成果

Y.Yoshino, A.Iwabuchi, K.Ishikawa, R.Onodera, M.Sugimoto, T.Shimizu, K.Katagiri: "Frictional properties of gamma-irradiated MoS^2 coating film and GFRP under fretting conditin at cryogenic temperatures"Proc. of the lnt. Tribology Conf. Nagasaki. 1461-1465

Y.Yoshino、A.Iwabuchi、K.Ishikawa、R.Onodera、M.Sugimoto、T.Shimizu、K.Katagiri：“低温下微动条件下伽马辐照 MoS^2 涂层膜和 GFRP 的摩擦特性”Proc

Y.Yoshino, A.Iwabuchi, K.Noto, N.Sakai, M.Murakami: "Vickers hardness properties of YBCO bulk superconductor at cryogenic temperatures"Physica C. 357-360. 796-798 (2001)

Y.Yoshino、A.Iwabuchi、K.Noto、N.Sakai、M.Murakami：“低温下 YBCO 体超导体的维氏硬度特性”Physica C. 357-360。

Y. Yoshino, A. Iwabuchi, K. Ishikawa, R. Onodera M. Sugimoto, T. Shimizu, K. Katagin: "Frictional properties of gamma-irradiated MoS2 coating film and GFRP under fretting condition at cryogenic temperatures"Proc. of the lnt. Tribology Conf. Nagasaki. 1461

Y. Yoshino、A. Iwabuchi、K. Ishikawa、R. Onodera M. Sugimoto、T. Shimizu、K. Katagin：“低温微动条件下伽马辐照 MoS2 涂膜和 GFRP 的摩擦特性”Proc。

Y.Yoshino,A.Iwabuchi,K.Ishikawa,R.Onodera,M.Sugimoto,T.Shimizu and K.Katagiri: "Frictional properties of gamma-irradiated MoS2 coating film and GFRP under fretting conditin at cryogenic temperatures"Proc.of the Int.Tribology Conf.Nagasaki 2000. (掲載予定).

Y. Yoshino、A. Iwabuchi、K. Ishikawa、R. Onodera、M. Sugimoto、T. Shimizu 和 K. Katagiri：“低温下微动条件下伽马辐照 MoS2 涂层膜和 GFRP 的摩擦特性”Proc.of Int.Tribology Conf.Nagasaki 2000。（待出版）。

Y.Yoshino, A.Iwabushi, R.Onodera, A.Chiba, K.Katagiri, T.Shimizu: "Vickers hardness properties of structural materials for superconducting magnet at cryogenic temperatures"Cryogenics. 41. 505-511 (2001)

Y.Yoshino、A.Iwabushi、R.Onodera、A.Chiba、K.Katagiri、T.Shimizu：“低温下超导磁体结构材料的维氏硬度特性”Cryogenics。