Abstract:
Due to the limited irradiation zone, development of small-scale test technology is of significant importance for the investigation of irradiation damage in nuclear materials. Micro-indentation tests and small punch tests(SPT) can efficiently evaluate irradiation hardening and embrittlement. However, the influence of the introduced indents by the micro-indentation tests to the SPT investigation need to be clarified and investigated. In the present study, the A508-3, a Chinese reactor pressure vessel(RPV) steel, and its model alloy (Fe-1.35Mn-0.75Ni) were used to investigate the effect of arbitrarily introduced indents on the SPT. Firstly, both micro-indentation tests and SPT indicate that hardness of A508-3 is significantly greater than the model alloy, accompanied by improved ductility. Electron backscattered diffraction(EBSD) results indicate that a quasi-uniform distribution of grains was observed in both specimens and the grains in A508-3 were obviously smaller than the model alloy. The strengthening of A508-3 was mainly ascribed to the refined grain strengthening and the solution strengthening. The improved ductility was possibly due to the increasing grain numbers or the density of grain boundaries. Secondly, SPT results indicate that, the obtained maximum load,
Pmax was obviously influenced by the introduced indents in softer specimen (the model alloy). The obtained ductility was hardly influenced by the introduced indents. For the practical materials, the introduced indents are expected to have minor influence on the data obtained by SPT.