Hydrogen Embrittlement Mechanism in Fatigue Behaviour of Austenitic and Martensitic Stainless Steels

G. Hénaff,Claus-Peter Fritzen,Hans-Jürgen Christ,Sven Brück,Volker Schippl

doi:10.1051/matecconf/201816522002

Abstract

In the present study, the influence of hydrogen on the fatigue behaviour of the high strength martensitic stainless steel X3CrNiMo13-4 and the metastable austenitic stainless steels X2Crni19-11 with various nickel contents was examined in the low and high cycle fatigue regime. The focus of the investigations was the changes in the mechanisms of short crack propagation. The aim of the ongoing investigation is to determine and quantitatively describe the predominant processes of hydrogen embrittlement and their influence on the short fatigue crack morphology and crack growth rate. In addition, simulations were carried out on the short fatigue crack growth, in order to develop a detailed insight into the hydrogen embrittlement mechanisms relevant for cyclic loading conditions.

Highlights

The demand for more efficient and cleaner technologies leads to the impulse to establish hydrogen as an energy carrier, for example in the automotive sector
The aim of this study is the identification of the changing microstructural mechanisms of fatigue crack initiation and crack propagation of microstructurally small fatigue cracks resulting from the presence of hydrogen in one martensitic and in two metastable austenitic stainless steels
The results of in-situ fatigue tests were presented, which were performed on two metastable austenitic stainless steels and one martensitic stainless steel at a test frequency of 1 Hz under varying tensile-compressive load in the LCF / HCF regime

Summary

Introduction

The demand for more efficient and cleaner technologies leads to the impulse to establish hydrogen as an energy carrier, for example in the automotive sector. This field of applications is already in the centre of research for a long time, where an important focus is put on a reliable and safe fatigue life prediction for weight-optimized and cyclically loaded components. Various theories are known from the literature that try to explain and describe these hydrogen effects and their basic mechanisms, such as HELP, HEDE, AIDE or HESIV (see for example the overview article by Lynch [1]) These mechanisms define idealized behaviour for special conditions and their relevance is strongly affected by stress and medium. The aim of this study is the identification of the changing microstructural mechanisms of fatigue crack initiation and crack propagation of microstructurally small fatigue cracks resulting from the presence of hydrogen in one martensitic and in two metastable austenitic stainless steels

Objectives

Methods

Findings

Conclusion