Reveal H-induced cracking in duplex stainless steel by neutron and x-ray diffraction and imaging

Purpose and goal:

The overall purpose is to develop a sample environment and perform operando time-of-flight neutron imaging and diffraction measurement to reveal local distribution of H, strain and microstructure evolution in duplex stainless steel under H charging and tensile loading. Despite of some delay, we have developed the sample environment and performed the neutron measurement at ISIS successfully.

Moreover, we have also performed operando synchrotron diffraction measurement at PETRA III. The results from the neutron and synchrotron measurements provide complementary information. Expected results and effects:

We have developed the sample environment and demonstrated the feasibility to utilize the time-of-flight neutron imaging and diffraction technique for in-situ and operando measurement to study hydrogen embrittlement. We will further improve the experiment setup and the hydrogen charging condition by using another electrolyte giving much higher hydrogen ingress in future work.

The project promotes industrial utilisation of neutron facilities and also create synergy between neutron and synchrotron facilities by developing sample environments for industrial users. Approach and implementation:

Neutron scattering and synchrotron radiation, the former with a high sensitivity to H and both with a high penetration power, provide unique possibilities to simultaneously detect H, strain, and H damage in metals. The project is a joint effort by corrosion expert at KTH Royal Institute of Technology, neutron expert at ESS, synchrotron expert at Lund University, and material expert at Alleima AB.

The combined expertise and good collaboration enabled the development of the sample environment and successful neutron and synchrotron measurements, showing the feasibility of the method.