Tribological and neutron radiation properties of boron nitride nanotubes reinforced titanium composites under lunar environment

The present study reports the tribological behavior, and radiation shielding performance of a multifunctional boron nitride nanotube (BNNT) reinforced titanium metal matrix composite (MMC) for applications in lunar exploration. BNNT-Ti MMCs showed 10.2 and 25.5% improvements in wear volume loss compared to pristine Ti samples with and without lunar simulant, respectively. For neutron radiation shielding evaluation, an additional set of samples with similar compositions was sintered at 750 °C. The decreased sintering temperature from 950 to 750 °C prevented BNNTs from interfacial reactions with the Ti matrix during sintering. The highest neutron attenuation was observed in BNNT-Ti MMC sintered at 750 °C, followed by the one sintered at 950 °C and pristine Ti sample. Maximum 45 and 50% improvements in linear and mass absorption coefficient were shown, respectively. This study proves that adding BNNTs to the Ti alloy matrix greatly enhanced the wear resistance, yield strength, and radiation shielding performance. Graphical abstract