Metallurgical Abstracts on Light Metals and Alloys vol.55

Crystallographic Analysis of Hydrogen Embrittlement Behavior in Aluminum Alloy using Diffraction Contrast Tomography

Kyosuke Hirayama*, Hiroyuki Toda**, Takafumi Suzuki**, Masayuki Uesugi***, Akihisa Takeuchi***
and Wolfgang Ludwig****
*Department of Materials Science and Engineering, Kyoto University
**Department of Mechanical Engineering, Faculty of Engineering, Kyushu University
***Research & Utilization Division, Japan Synchrotron Radiation Research Institute
****European Synchrotron Radiation Facility

[Published in Materials transactions, Vol. 63, Issue 4 (2022), pp. 586–591]

https://doi.org/10.2320/matertrans.MT-L2021020
E-mail: toda[at]mech.kyushu-u.ac.jp
Key Words: Aluminum alloy, Hydrogen embrittlement, Intergranular fracture, Quasi-cleavage fracture, Diffraction contrast tomography

Crystallographic assessment of the hydrogen embrittlement behavior of Al-Zn-Mg alloy was performed by means of a technique combining fracture trajectory analysis and synchrotron X-ray diffraction contrast tomography. The 3D microstructure reconstructed using diffraction contrast tomography contained 119 grains. Fracture surfaces revealing intergranular fracture, ductile fracture, and quasi-cleavage fracture were observed in the alloy. While the intergranular crack initiated at a grain boundary with high grain boundary energy and a high angle between the grain boundary plane and loading direction, the crack propagation itself was not observed to be sensitive to these two parameters. The quasi-cleavage fracture surfaces were not characterized by any specific crystal orientation because of variation in the free surface segregation energy of hydrogen uniforms without depending on surface orientation.

3D DCT reconstruction of grains in Al-Zn-Mg alloy. Colors according to IPF key shown in the inset.