Recent Progress in Subsized Charpy Impact Specimen Testing for Fusion Reactor Materials Development

Recent Improvements in Size Effects Correlations for DBTT and Upper Shelf Energy of Ferritic Steels

“…[he full size specimen dimensions are in accordance with ASTM standard E23-86. While there are no standards available for subsize specimens, the dimensions used in this study for half and third Size specimens are similar to those used in other investigations (1)(2)(3)(4)(5)(6)(7)(8). Note that the half size and third size specimens have the same length.…”

“…An alternative approach was used to calculate lt based against the model presented in this paper. In another paper, Lucas et al, (6) showed that the fracture stress is related to Pmby the equation o1"= 6.52Pm/Bb (3) which leads to the equation…”

An evolution of understanding of reactor pressure vessel steel embrittlement

“…Key to early work was the demonstration of quantitative relationships between changes in microhardness and changes in yield strength, allowing microhardness tests to serve as a means of tracking radiation hardening [43][44][45]. Moreover, UCSB developed techniques to automate microhardness testing on an array of specimens -primarily 3 mm diameter discs [46].…”

“…As illustrated in Fig. 6, his early work in demonstrating quantitative relationships between hardness changes, yield stress changes, and Charpy transition temperature shifts [29,33,[43][44][45]58] has been reinforced by later work laying out the theory underlying these relationships. He and coworkers have developed computer simulations of dislocations moving through a field of obstacles based on the work of Foreman and Makin [59], as illustrated in Fig.…”

“…(1) The development of robust models of irradiation hardening and transition temperature shift (TTS) in RPV steels based on the evolution of several predominant defect types in irradiated RPV steels, including precipitates (e.g., Cu rich for high Cu steel, Mn-Ni rich in low-Cu steels at high fluences), stable matrix defects, and unstable matrix defects (UMDsvacancy agglomerates, partially affiliated with Cu and/or other alloys) [34][35][36][37][38]44,48,50,51,[74][75][76][77][78] (2) The evolution of the Cu-Ni-Mn precipitate population by radiation-enhanced diffusion processes and the employment of rate theory models calibrated with extensive data to predict that evolution [27][28][29]31,32,35] (3) The role of Cu, Mn, Ni in mitigating the damage microstructure [31][32][33][34][35]45,50,71,73,74] -for instance: a. a threshold level of bulk Cu before the onset of hardening;…”