Elastic modulus of nanocrystalline titanium evaluated by cyclic tensile method

The present study is devoted to examinations of the elastic modulus with the use of the uniaxial tensile test. The commertial purity titanium Grade 2 in the two states i.e. microcrystalline (mc-Ti) and nanocrystalline (nc-Ti) were examined. Bulk nc-Ti was fabricated by hydrostatic extrusion (HE) which is one of the severe plastic deformation methods (SPD). The elastic modulus of mc-Ti and nc-Ti were compared with the aim to analyze the influence of the nanostructure of titanium on its elastic modulus. The mc-Ti and nc-Ti samples were subjected to uniaxial tensile tests at various strain rates and various values of stress.Generally, higher elastic modulus values were obtained in microcrystalline titanium. The elastic modulus of mc-Ti was evaluated at 107 GPa on average, whereas the elastic modulus of nc-Ti was 94 GPa on average. The nanocrystalline titanium had a lower elastic modulus than its microcrystalline counterpart by 13% on average, which can be attributed to the presence of significant volume of amorphous regions in the structure. Moreover, in this case a lower standard deviation of all the results was obtained. In most cases, with higher applied stress (load) the value of the modulus was lower, whereas at higher strain rates its value was higher.