Liquid helium free cryogenic mechanical property test system with optical windows

Cryogenic Engineering Conference 2017

材料科学;物理学

Zhang, H.C.^1,2 ; Huang, C.J.^1 ; Huang, R.J.^1,2 ; Li, L.F.^1,2

State Key Laboratory of Technologies in Space Cryogenic Propellants, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing

100190, China^1

University of Chinese Academy of Sciences, Beijing

100049, China^2

关键词: Cryogenic temperatures;    D. digital image correlation (DIC);    Environmental temperature;    G-m cryocooler;    In-plane displacement;    Optical window;    Surface displacement;    Uniaxial tensions;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/278/1/012083/pdf
DOI  :  10.1088/1757-899X/278/1/012083

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

Digital image correlation (DIC) is a non-contact optical method for the in-plane displacement and strain measurement, which has been widely accepted and applied in mechanical property analysis owing to its simple experimental steps, high accuracy and large range of measurement. However, it has been rarely used in cryogenic mechanical test since the opaque design of cryostats and the interaction of optics with liquid coolants (liquid nitrogen or liquid helium). In the present work, a liquid helium free cryogenic mechanical property test system cooled by G-M cryocoolers, with a continuous, tunable environmental temperature from room temperature down to around 20 K, was developed and tested. Quartz optical windows, which are compatible with 2D DIC technology, were designed and manufactured on both inner and outer vacuum chambers. The cryogenic test system with optical windows satisfies well for mechanical tests of materials and takes advantage of both being compatible with DIC technology and getting rid of the use of expensive liquid helium. Surface displacement and strain field of Ti6Al4V under uniaxial tension were studied at 20 K by using this system. The results obtained by DIC method agree well with those obtained by extensometers at cryogenic temperatures.