*Article* **Role of Hydrogen-Charging on Nucleation and Growth of Ductile Damage in Austenitic Stainless Steels**

#### **Eric Maire 1,\*, Stanislas Grabon 1, Jérôme Adrien 1, Pablo Lorenzino 1, Yuki Asanuma 2, Osamu Takakuwa 3,4,5 and Hisao Matsunaga 3,4,6**


Received: 6 February 2019; Accepted: 19 April 2019; Published: 1 May 2019

**Abstract:** Hydrogen energy is a possible solution for storage in the future. The resistance of packaging materials such as stainless steels has to be guaranteed for a possible use of these materials as containers for highly pressurized hydrogen. The effect of hydrogen charging on the nucleation and growth of microdamage in two different austenitic stainless steels AISI316 and AISI316L was studied using in situ tensile tests in synchrotron X-ray tomography. Information about damage nucleation, void growth and void shape were obtained. AISI316 was found to be more sensitive to hydrogen compared to AISI316L in terms of ductility loss. It was measured that void nucleation and growth are not affected by hydrogen charging. The effect of hydrogen was however found to change the morphology of nucleated voids from spherical cavities to micro-cracks being oriented perpendicular to the tensile axis.

**Keywords:** X-ray tomography (X-ray CT); 3D image analysis; damage; hydrogen embrittlement; stainless steel
