High Temperature Flow Response Modeling of Ultra-Fine Grained Titanium
This work presents the mechanical behavior modeling of commercial purity titanium subjected to severe plastic deformation (SPD) during post-SPD compression, at temperatures of 600-900 °C and at strain rates of 0.001-0.1 s−1. The flow response of the ultra-fine grained microstructure is modeled using the modified Johnson-Cook model as a predictive tool, aiding high temperature forming applications. It was seen that the model was satisfactory at all deformation conditions except for the deformation temperature of 600 °C. In order to improve the predictive capability, the model was extended with a corrective term for predictions at temperatures below 700 °C. The accuracy of the model was displayed with reasonable agreement, resulting in error levels of less than 5% at all deformation temperatures.
Hot Deformation Behavior of Ultra-Fine Grained Pure Ti
In the present study, compression tests were performed at a strain rate of 0.001 to 0.1 sˉ1 and in the range of 600°C to 900°C to investigate the high temperature deformation behavior and flow stress model of commercially pure titanium after severe plastic deformation (SPD). It was found that the effects of temperature and strain rate are significant in dictating the steady state flow stress levels. Flow accompanied by thermal softening was observed due to a combination of dynamic recovery and recrystallization for deformation at or above 600°C. Furthermore, microstructural evolutions of the as processed and hot deformed material were investigated. Based on constitutive equations, the flow stress was modeled for this light ultra-fine grained (UFG) material. The validity of the model was demonstrated with satisfactory agreement in light of the experimental mechanical behavior.
Researches on Structural Factor Involvement in Oral Tribology
This study is focused on two ceramic materials, D.SING (Ivoclar) and VM13 (emphasis the VITA TN), frequently used in restorative dentistry practice and it comes to complete a full set of results obtained by the authors over several years of research on oral tribology with main influence on oral health. In this way there are involved more specific structural aspects of dental restorative ceramic materials quality as is shown in [1].