In Situ Characterization of 17-4PH Stainless Steel by Small-Angle Neutron Scattering

17-4PH martensitic steel is usually used as valve stems in nuclear power plants and it suffers from thermal aging embrittlement due to long-time service a high-temperature high-pressure environment. Here, we characterized the evolution of microstructures at nano-scale by situ small-angle neutron scattering (SANS) with thermo-mechanically coupled loading device. The device could set different temperatures tensile so that an SANS experiment dynamically characterize process nanoscale structural changes. results showed increasing time, ε-Cu phase precipitates grows temperature 475 °C 590 °C, spherical but became elongated cylinders °C. Moreover, stress aid growth