This work reports the first mechanical properties of Ti3AlC2-Ti5Al2C3 materials neutron irradiated at ∼400, 630 and 700°C at a fluence of 2×1025nm−2 (E>0.1MeV) or a displacement dose of ∼2dpa. After irradiation at ∼400°C, anisotropic swelling and loss of 90% flexural strength was observed. After irradiation at ∼630–700°C, properties were unchanged. Microcracking and kinking-delamination had occurred during irradiation at ∼630–700°C. Further examination showed no cavities in Ti3AlC2 after irradiation at ∼630°C, and MX and A lamellae were preserved. However, disturbance of (0004) reflections corresponding to M-A layers was observed, and the number density of line/planar defects was ∼1023m−3 of size 5–10nm. HAADF identified these defects as antisite TiAl atoms. Ti3AlC2-Ti5Al2C3 shows abrupt dynamic recovery of A-layers from ∼630°C, but a higher temperature appears necessary for full recovery.