Prototype design of an SEM capable of detecting helium desorption during high temperature tensile test

能够检测高温拉伸试验期间氦解吸的 SEM 原型设计

• 批准号: 05555164
• 负责人: KIMURA Akihiko
• 金额: $ 9.28万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Developmental Scientific Research (B)
• 财政年份: 1993
• 资助国家: 日本
• 起止时间: 1993 至 1994
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-05555164/
• 关键词: Fusion reactor materials; helium effects; Scanning electron microscope; vanadium alloys; helium embrittlement; high temperature strength; tritium trick; 走査電子顕微鏡; 電顕内高温引張; ガス分析; 水素脆化; 金属間化合物; その場観察; 照射効果; 高温変形

A large amount of helium is generated in fusion reactor materials by 14MeV neutron irradiation leading to so called high temperature helium embrittlement. The mechanism of helium embrittlement is believed to be due to the accumulation of helium to grain boundaries where grain boundary cohesion is severely impaired. The details of the mechanism, however, are still not known yet. In the present project, a commercially available scanning electron microscope (SEM) is customized in such a way that helium desorbed from deforming specimen at high temperature can be detected along with in situ observation. Thereby the relation between helium desorption and slip band formation and crack opening is examined in order to investigate the mechanism of helium embrittlement.Main functions of this apparatus are : (1) magnified observation of specimen surface, (2) in situ tensile test capability, (3) specimen heating, (4) helium desorption detection, etc. A lead screw type tensile mechanism has been ado … More pted driven by a stepping motor. Specimen heating was done by direct electrical heating. This method lacks in uniformity in temperature while temperature response is superior and the volume of the heated zone can be minimized. Temperature measurement is done using a thermocouple attached to the specimen grip. Actual temperature of the specimen is obtained by calibrating using a dummy specimen on which thermocouple is attached in the central part of the gage portion. A quadrupole mass spectrometer is used to measure the helium desorption.Several iteration cycles were necessary to optimize the shielding of thermal electrons without obstructing the view area. The apparatus with intended functions has been successfully constructed. Vanadium alloy specimens doped with tritium trick have been tensile-tested in situ in this apparatus. Stress-strain curves and helium desorption curves were recorded simultaneously with video-images of SEM images on a VTR.Some of the important findings from these experiments are that helium desorption occurred in synchronous with crack opening at the specimen surface. Less

14 MeV中子辐照在聚变堆材料中产生大量的氦，导致所谓的高温氦脆。氦的脆化机制被认为是由于氦在晶界堆积，晶界凝聚力严重受损。然而，这一机制的细节仍不清楚。在本项目中，定制了一种商用扫描电子显微镜(SEM)，使其能够在原位观察的同时检测到高温变形样品中脱附的氦。该装置的主要功能是：(1)放大观察试件表面，(2)原位拉伸试验能力，(3)试件加热，(4)氦脱附检测等。该装置的主要功能是：(1)放大观察试件表面，(2)原位拉伸试验能力，(3)试件加热，(4)氦脱附检测等。该装置的主要功能是：(1)放大观察试件表面；(2)原位拉伸试验；(3)试件加热；(4)氦脱附检测等更多的是由步进电机驱动。样品加热采用直流电加热。该方法温度不均匀，温度响应性好，可使加热区的体积最小。温度测量是使用连接到样品握把上的热电偶进行的。样品的实际温度是通过使用一个虚拟样品进行校准的，在该虚拟样品上，热电偶连接在量规部分的中心部分。用四极质谱计测量氦的脱附，为了在不遮挡视场的情况下优化热电子的屏蔽，需要几次迭代循环。研制成功了具有预期功能的仪器。在该装置上对掺氚钒合金样品进行了原位拉伸试验。用扫描电子显微镜的视频图像同时记录了应力-应变曲线和氦的脱附曲线。这些实验的一些重要发现是氦的脱附与试件表面的裂纹张开同步发生。较少

项目成果

A.Kimura: "Microtructural evolution of low activation ferritic alloys under neutron irradiation." J.Nucl.Mater.(in press). (1994)

A.Kimura：“中子辐照下低活化铁素体合金的微观结构演化。”

A.Kimura: "Critical pressures of water vapor and hydrogen gas causing intergranular brittle fracture of Co3Ti at room temperature" Materians Trane.JIM. 35. 879-887 (1994)

A.Kimura：“室温下水蒸气和氢气的临界压力导致 Co3Ti 晶间脆性断裂”Materians Trane.JIM。

Akihiko Kimura: "Impact Properties of Intermetallic Compounds" Materials Science and Engineering. (in press). (1994)

木村明彦：《金属间化合物的冲击性能》材料科学与工程。

A.Kimura: "Designation of alloy composition of low activation martensitic steel." J.Nucl.Mater.(in press). (1994)

A.Kimura：“低活化马氏体钢合金成分的命名。”

H.Matsui: "R&D of Vanadium Alloys for Fusion in Japan" “Materials of Advanced Energy Systems. 271-276 (1994)

H.Matsui：“日本聚变用钒合金的研发”“先进能源系统材料”271-276（1994）