The implementation and reflection of the "4R-4M" experimental methodology in the design and construction of experimental facilities in major national science and technology infrastructure

Currently, China is in an important period for economic development, with a large number of major strategic projects being successively constructed and operated, such as the development of strategic petroleum reserves, long-distance multinational oil pipelines, the storage and transportation of high-sulfur oil and gas field, the construction of large-scale nuclear power plant, supercritical thermal power plant, high-speed railways, and more. The engineering materials employed in these major strategic projects possess unique characteristics such as "super-large structural dimensions", "super-strong material performance", "under extreme and multi-factor coupling service environments", and "the coexistence and interplay of multiple failure modes". These characteristics impose new challenges in terms of the safety service and evaluation of engineering materials and industrial equipment. To address these challenges, it is essential to investigate the underlying mechanisms of mechanical and structural changes, as well as the various factors that influence material performance under real-world conditions. However, most cutting-edge scientific research often simplifies experiment conditions, which can significantly deviate from the actual working conditions and production environments in industrial settings. It is therefore crucial to develop characterization protocols that can accurately replicate the extreme temperatures, pressures, and chemical environments, while ensuring precise detection capabilities and high resolution measurements for comprehensive analyses. This article reviews the developments of in-situ characterization techniques in various cutting-edge materials research and introduces the "4R-4M" experimental methodology. The "4R" aspect focuses on conducting real-time research on real materials to study real processes under operational conditions, while the "4M" aspect emphasizes the utilization of multiple techniques to enable multi-scale, multi-dimensional, and multi-modal characterizations. By developing the "4R-4M" experimental system, it becomes possible to carry out real-time evaluations of different physical and chemical properties of engineering materials under industrial conditions. This article further discusses the practical implementation of the "4R-4M" experimental methodology in the design and construction of large-scale scientific facilities. For example, the National Materials Service Safety Assessment Facilities (MSAF) have specifically designed and constructed a set of experimental facilities to replicate different service environments and accurately reproduce failure processes for large-scale engineering materials. Furthermore, this article discusses the current development trend for integrating various X-ray techniques in experimental stations at world-renowned synchrotron radiation light sources, such as the SPring-8 light source in Japan, Soleil light source in France, and Shanghai synchrotron radiation facility (SSRF). The advancement in technology integration, multi-scale characterization, multi-dimensional detection, and multi-modal analysis is highlighted as a significant achievement. The Shenzhen Innovation Light Source has implemented the "4R-4M" experimental methodology in the design of beamlines for high-tech industries, including the integrated circuits, biomedicine, advanced materials, and advanced manufacturing. The primary goal is improve key technologies and driving progress in the industry.