Browsing by Author "Uz, M. M."

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • Placeholder
    ArticlePublicationMetadata only
    A comparative study on phenomenological and artificial neural network models for high temperature flow behavior prediction in Ti6Al4V alloy
    (Elsevier, 2022-12) Uz, M. M.; Hazar Yoruç, A. B.; Çokgünlü, Okan; Aydoğan, C. S.; Yapıcı, Güney Güven; Mechanical Engineering; YAPICI, Güney Güven; Çokgünlü, Okan
    Due to its critical use in lightweight components requiring elevated temperature operation, it is very important to determine and model the high temperature thermomechanical flow behavior of Ti6Al4V. In this study, uniaxial tensile tests were performed at quasi-static strain rates and at temperatures ranging from 500 °C to 800 °C. The ductile behavior provided at a temperature of 800 °C and at a strain rate of 0.001 s−1 can be preferred for forming operations due to the steady state flow behavior. However, stress peaks during deformation at the strain rates of 0.1 s−1 and 0.01 s−1 are indicative of an unsafe zone. For modeling the flow stress behavior, three models including the Artificial Neural Network, Modified Hensel-Spittel and Arrhenius are employed with varying prediction performance as shown by the correlation coefficient (R) and average absolute relative error (AARE) values. Accordingly, the Artificial Neural Network model is claimed to be a more suitable approach for capturing the mechanical behavior of Ti6Al4V within the forming temperature range utilized in this study.
  • Placeholder
    ArticlePublicationMetadata only
    A comparative study on the high-temperature forming and constitutive modeling of Ti-6Al-4V
    (Springer, 2022-09-28) Uz, M. M.; Hazar Yoruç, A. B.; Aydoğan, C. S.; Yapıcı, Güney Güven; Mechanical Engineering; YAPICI, Güney Güven
    Ti-6Al-4V alloy is often preferred for high-performance components such as aerospace components due to its superior material properties and thermal resistance. In order to produce these components in the desired geometry, it is very important to determine the high-temperature thermomechanical properties of Ti-6Al-4V. In order to define these properties, uniaxial tensile tests at strain rates of 0.001, 0.01 and 0.1 s−1 at 700, 750 and 800 °C were applied in this study. In tests performed at a strain rate of 0.001 s−1 at 800 °C, an elongation at break above 0.8 representing a dominant ductile behavior is observed. It is clearly demonstrated that the initial 17.32% β phase reaches 31.02% at 800 °C, and the α grain size increases with temperature. Existence of dimples and voids in the fracture surfaces are an indicator of increased ductility behavior. In addition to the Modified Johnson–Cook model, which is widely used for modeling flow stress, the use of the extended Ludwik equation is suggested in this study. According to the correlation coefficient (R), it is claimed that the Extended Ludwik model is a more suitable approach for modeling the mechanical behavior for the studied forming temperature range.