The study focused on the hydrogen embrittlement (HE) behavior of three alloys: the CoCrFeMnNi high-entropy alloy (HEA), 304 stainless steel (304SS), and an alloy identified as IN718. The research involved slow strain rate tensile tests and fracture surface analysis before and after electrochemical hydrogen pre-charging. An equiatomic CoCrFeMnNi ingot was used, and pure metals (>99.9 wt.%) were utilized during the process. The findings showed that the HEA exhibited the greatest resistance to HE, followed by 304SS and IN718 alloy, when the alloys were charged at 1.79 mA cm-2 for 24 h and 48 h, and 179 mA cm-2 for 2 h. The 304SS and IN718 alloys showed a reduction in ductility due to hydrogen, while the hydrogen-affected fracture strain of the HEA depended on the hydrogen charging time. The resistance to HE improved with a short hydrogen charging time of 24 hours, but it reduced at the 48-hour charging time. This is due to the competing mechanisms between hydrogen-enhanced twin formation and hydrogen-enhanced decohesion (HEDE). The study also found that the number of nano twins (2.71) and the width of stacking fault (SF) bundles (5.77 nm) in the hydrogen-assisted brittle zone was greater than in uncharged samples (2.57 and 5.02 nm). This clearly demonstrates that the presence of hydrogen promotes the formation of stacking faults and twins in CoCrFeMnNi alloy.

Author(s) Details:

Xinfeng Li,
Sino-French Institute of Nuclear Engineering and Technology, Sun Yat-Sen University, Zhuhai, 519082, China.

Zheng Feng,
State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, China.

Xiaolong Song,
State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, China.

Tang Gu,
College of Mechanical and Electrical Engineering, Harbin Engineering University, Harbin, 150001, China.

Yong Zhang,
State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing, 100083, China.

To Read the Complete Chapter See Here

 

By Editor

Leave a Reply