Abstract: To understand the effect of irradiation on SiC_p/Al composites for aerospace electronic components packing substrates, 3 MeV Fe¹¹⁺ beam was used to carry out irradiation experiments under different ion fluence. After irradiation, X-ray diffraction (XRD) and nano-indentation were used to characterize and analyze the materials. XRD analysis indicated that the stress of irradiated layer changed after Fe¹¹⁺ ions’ incidence. Combined with the corresponding theoretical model, the dislocation density of aluminum matrix was calculated. It was found that the dislocation density of aluminum matrix increased, and the SiC particles were amorphized after irradiation. The measurement of nano-indentation revealed that the irradiation hardening of the material increased with the increase of ion fluence. It can be deduced that the irradiation hardening may be due to the stress changes in aluminum alloy matrix leading to the generation of local high-density dislocation regions, which impedes the subsequent dislocation movements, and ultimately increases the hardness of the material.