Void growth and coalescence in irradiated copper under deformation

Abstract

A decrease of fracture toughness of irradiated materials is usually observed, as reported for austenitic stainless steels in Light Water Reactors (LWRs) or copper alloys for fusion applications. For a wide range of applications (e.g. structural steels irradiated at low homologous temperature), void growth and coalescence fracture mechanism has been shown to be still predominant. As a consequence, a comprehensive study of the effects of irradiation-induced hardening mechanisms on void growth and coalescence in irradiated materials is required. The effects of irradiation on ductile fracture mechanisms -void growth to coalescence -are assessed in this study based on model experiments. Pure copper thin tensile samples have been irradiated with protons up to 0.01 dpa. Micron-scale holes drilled through the thickness of these samples subjected to uniaxial loading conditions allow a detailed description of void growth and coalescence. In this study, experimental data show that physical mechanisms of micron-scale void growth and coalescence are similar between the unirradiated and irradiated copper. However, an acceleration of void growth is observed in the later case, resulting in earlier coalescence, which is consistent with the decrease of fracture toughness reported in irradiated materials. These results are qualitatively reproduced with numerical simulations accounting for irradiation macroscopic hardening and decrease of strain-hardening capability.

Effect of dislocation channeling on void growth to coalescence in FCC crystals

“…Distance be-455 tween slip traces is very low compared to the distance far from the voids. Voids shape after coalescence tends to be similar to what is typically observed in materials deforming homogeneously [68,82]. At the very end of one test (Fig.…”

“…19a. [82] with the Finite Element Method (FEM). Details about the reference simulation can be found in [82], and a typical mesh used in shown on Fig.…”

Effect of Residual Stress Distribution on the Formation, Growth and Coalescence of Voids of 27Cr White Cast Iron under Impact Loading

“…This voids coalescence mechanism is also reported for the different alloys. 30,31) Based on the above analysis, effect of impact force on fracture surface of the 27Cr white cast iron is evaluated. The fracture behavior of alloy involves the cracks initiation, growth and propagation.…”

Investigating radiation damage in nuclear energy materials using JANNuS multiple ion beams

“…In the last decade, many materials of interest for the nuclear industry have been investigated at the JANNuS platform. A non-exhaustive list includes: nuclear fuel and surrogates such as uranium dioxide [30][31][32][33]; neutron absorber like B4C [34,35]; structural alloys for present, advanced and future fission and fusion systems as well as model metals such as iron, Fe-Cr alloys and ferritic-martensitic steels [36][37][38][39], ODS steels [40][41][42][43][44][45], austenitic steels [46][47][48][49][50][51], tungsten and copper [52][53][54], aluminum alloys [55], zirconium [56][57][58]; Enhanced Accident Tolerant Fuel [59,60]; advanced structural ceramics for innovative nuclear systems such as carbides and nitrides [61][62][63][64][65]; glasses and oxides for waste management [66][67][68][69]; advanced coatings for Liquid Metal fast Reactors [70]; polymers for cable sheath or glove box components [71]. Selected studies are presented in the following that exemplify the prime role of in s...…”