Elastic properties of in-situ processed Ti–TiB composites measured by impulse excitation of vibration

The elastic moduli, shear moduli and the Poisson ratios of four different in-situ processed titanium (Ti) composites consisting of titanium monoboride (TiB) whiskers were measured using a dynamic method based on impulse excitation of vibration. For comparison, elastic modulus measurements were also made using tensile specimens with strain gages bonded to the specimen. The Ti–TiB composites consisted of 30, 54, 69, and 83 vol.% of TiB whiskers. The 83 vol.% TiB composite also consisted of 7 vol.% TiB2 phase. The study also included a TiB–TiB2 composite containing 16 vol.% TiB2 phase. The elastic and shear moduli of all the composites were found to increase with an increase in the volume fraction of TiB. The Poisson ratio decreased with increasing vol.% of TiB. The dynamic elastic modulus data were found to be in reasonable agreement with the tensile elastic modulus data. The variations in elastic properties with the vol.% of TiB whiskers are assessed in the light of theories on effective elastic response of two phase composites. The probable values of the elastic modulus, the shear modulus, and the Poisson’s ratio of the TiB phase were also estimated using these theories.