Murthy Kolluri

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/63294

#### **Abstract**

A literature review on highly irradiated 5*xxx* and 6*xxx* series Al alloys is conducted to understand the expected changes in mechanical properties of high flux reactor (HFR) vessel material in relation with microstructural aspects beyond the current surveillance data to support the HFR Surveillance Program (SURP). It was found that the irradiation swelling in 5*xxx* series alloys is not a crucial degradation mechanism. Dislocation damage is expected to reach a saturation limit in both 5*xxx* and 6*xxx* series alloys at relatively low fast-fluence values (<2 × 1026 n/m2 ). The damage caused by precipitation of transmuta‐ tion Si is found to be the dominant mechanism affecting the fracture toughness proper‐ ties of irradiated 5*xxx* and 6*xxx* series Al alloys at high thermal fluence values. Tensile and fracture toughness data collected from the literature up to very high thermal fluences are analyzed in comparison with the available HFR surveillance data to predict the behavior of the HFR vessel material beyond current surveillance data. The observed changes in mechanical properties are classified into four different regimes. The contribution of various irradiation damage mechanisms, namely the displacement damage and transmutation damage, to the evolution of microstructure and mechanical properties is discussed in all four regimes for 5*xxx* and 6*xxx* series alloys.

**Keywords:** irradiation defects in aluminum alloys, displacement damage, transmuta‐ tion damage, Mg2Si precipitates, fracture toughness, radiation hardening, embrittle‐ ment
