Abstract by Richard Cass
Physics and Astronomy
Materials Properties of Tungsten Infiltrated Carbon Nanotube Structures
To show that mechanically robust MEMS devices can be made out of Carbon Nanotube Structures, an experiment to determine the materials properties of Tungsten Infiltrated Carbon Nanotube structures (WCNT's) was developed. CNT beams were grown, infiltrated with tungsten, then broken using a 3-Point bending process. Because it was found that the beams were not uniformly infiltrated by the tungsten, a new model was developed considering the tungsten to be a shell on the outside of the beam. With this model, the Ultimate Strength of annealed WCNT beams was found to be 447 MPa with a Young's Modulus of 110 GPa, compared to the values of bulk tungsten: 3900 MPa and 405 GPa respectively. Due to the difficulty of determining the width of the shell, a new test is now being developed to calculate the Young's Modulus of thinner WCNT's from the resonant frequency of WCNT beams, obtained from a Laser Doppler Vibrometer.