Zihao Wang
I have been focusing on ensuring the reliability of structural materials in extreme environments, particularly with an emphasis on the grain boundary strength and a hardening effect of intermetallics in Ni and Fe based alloys. My current project will make use of the most ambitious in-situ observation methods to clarify and visualise the role of diffusible hydrogen in crack evolution mechanistically, which goes beyond the current state-of-the-art. My aim is to reduces the repair rate of key components in the power plant, which will bring huge budget savings according to the current energy strategy. In the long-term perspective, a safe and low-cost energy will increase social welfare by providing low electricity prices, promote a decarbonised society, and achieve the ambitious goal of net-zero emissions.
Breaking frontiers in stress corrosion cracking of nickel-based alloys from the perspective of diffusible hydrogen
Nuclear energy is forecast by the European Commission to make a significant contribution to achieving a low-carbon, affordable energy, enhancing energy security during the development of renewables. However, stress corrosion cracking (SCC) is one of the biggest obstacles, as it induces unexpected failure to nuclear power plant components, threatening operational safety. Mitigating SCC requires a thorough understanding of its mechanisms, of which the current understanding is limited. In recent years, it has found that diffusible hydrogen plays a critical role in the evolution of SCC, which is beyond the existing understanding. Therefore, this project aims to uncover new SCC mechanisms in Ni-based alloys and stainless steel (materials used in nuclear power plants) from the perspective of the role of diffusible hydrogen, based on the good foundation of our previous work. The multi-scale experimental approach will focus on in-situ materials characterisation of Ni-based alloys and stainless steel during mechanical testing with in-situ hydrogen charging. The results have the potential to provide practical suggestions and guidance to our end-users for producing alloys with higher SCC-resistance for a safer utilisation of nuclear energy.
Characterising crack tip to understand SCC mechanism (a) HAADF image at the GB of the Ar-exposed specimen; and the related (b, c, and d) magnified TEM-BF, HAADF, and O intensity images of the oxide tip of the GB; (e) HAADF image at GB for the H-exposed specimen, and the related (f) magnified TEM-BF image of the oxide tip of the GB.
