The role of Cr concentration and temperature on cavity swelling with co-injected helium in dual-ion irradiated Fe and Fe-Cr alloys

•The non-monotonic nature of the cavity swelling behavior is related to the ratio of biased to unbiased sink strengths.•Cr dependence of swelling may be affected by solute trapping of defects leading to increased point defect recombination.•Higher He implantation rate causes a shift in the swelling peak to higher temperatures in both Fe and Fe-Cr alloys.•A bimodal cavity size distribution was observed in the 10 appm He/dpa samples, but not for 0.1 appm He/dpa.•Cr-enriched precipitates were observed in the Fe-14Cr sample irradiated at 400 °C.