Preparation of Boron Nitride Nanotube/Aluminum Matrix Composites and Their Application in Automotive Connecting Rods

In order to address the urgent demand for high-performance materials in the field of automotive lightweighting, there is a need for solutions to the interface instability and performance degradation of traditional reinforcing phases (e.g., SiC, CNT) at elevated temperatures. The present study prepared BNNTs/Al composites via the stirred casting method for automotive connecting rods. The microstructure, interface characteristics, phase evolution, and high-temperature wettability were systematically characterised using a range of analytical techniques, including SEM, TEM, XRD, and DSC. A study was conducted to assess the mechanical properties of the composites in comparison to those of conventional 40Cr steel. This investigation enabled an evaluation of the material's comprehensive performance for use in automotive connecting rods. The study successfully achieved uniform dispersion of BNNTs within the aluminium matrix, forming tightly bonded, semi-coherent interfaces such as Al/AlN and Al/AlB₂. It was found that complete wetting was achieved at 675 °C, with interface reactions generating AlN and AlB₂ phases that significantly enhanced performance. The prepared connecting rod demonstrates a specific strength that significantly exceeds that of 40Cr steel. The experimental investigation conducted in a controlled setting yielded notable outcomes. The empirical evidence demonstrated a 6.5% enhancement in braking performance and a 5.8% reduction in fuel consumption. Through the optimisation of interface design and process control, the BNNTs/Al composite achieves a balanced compromise between high strength, low density, and excellent thermal stability. The material's potential for use in lightweight automotive connecting rods is significant, offering a novel approach to the eco-friendly manufacturing of related components.