Boron nitride nanotubes (BNNTs), renowned for their high thermal conductivity and excellent thermal stability, are widely used to reinforce aluminum (Al) matrix composites. However, the influence of BNNT morphology on their strengthening behavior remains to be further investigated. Here, we systematically investigate the critical role of BNNT morphology—specifically boron nitride nanorods (BNNRs), flexible multiwalled BNNTs (F‐MWBTs), and rectilinear multiwalled BNNTs (R‐MWBTs)—in governing the microstructural evolution, fracture behavior, and mechanical performance of Al matrix composites. R‐MWBTs with regular morphology disperse more uniformly along grain boundaries, influencing grain boundary evolution and enhancing grain refinement, whereas BNNRs and F‐MWBTs are more prone to agglomeration, resulting in differences in load‐transfer efficiency and microstructural regulation. The Al/R‐MWBT composites achieve a yield strength of 275 MPa and an ultimate tensile strength (UTS) of 320 MPa, representing a 76% improvement over the Al matrix while maintaining fracture elongation above 10%. These results highlight the influence of BNNT morphology on the reinforcement behavior of Al‐based composites.
Wang et al. (Wed,) studied this question.