Experimental Determination of the Elastic Tensor of Trigonal B4C Using Resonance Ultrasound Spectroscopy

Boron carbides are a class of material known for their particularly low density compared to their hardness. As such, boron carbide is readily utilized in commercially available body armor as ballistics protection. While the elastic properties of isotropic boron carbide have been well characterized by experimental means, the full trigonal R[endif]-->m elastic tensor of B4C and the anisotropic elastic properties of B4C have only been determined via density functional theory calculations. Resonance ultrasound spectroscopy (RUS) is an experimental method that can correlate the resonant frequencies of a material with known dimensions and mass to the elastic tensor of that material. Here, we used RUS to measure and derive the full trigonal elastic tensor of a mono-crystal B4C, which were then compared to those from isotropic mechanical results and DFT-derived determinations. Based on the new elastic tensor values, we further determine the elastic moduli of B4C, including bulk modulus, shear modulus, Young’s modulus, and Poisson’s ratio.