Investigation on Cracking Behavior and Development of a Fracture Model of Ti-47Al-2Nb-2Cr Alloy During Hot Deformation

When alloys are strained toa certain limit under the plastic deformation, ductile fracture occurs. Whether the required deformation can be put into effect before fracture appearshas become a serious concern. A combination ofcompressiontests, ductile fracture criteria as well as finite element simulation (FEM) wereemployed in this study to establish the fracture initiation prediction model of Ti-47Al-2Nb-2Cr alloy. To obtain the critical fracture strain, atechnique was proposed to calculate the data for deformed cylindrical samples through isothermal compression tests in the temperature range between 1223 and 1423K with strain rates ranging from 0.001 to 1s(-1). Five commonly used ductile fracture criteria were compared by FE simulation of compressing tests. It was found that the Brozzo criterion wasfound to be suitable and accordingly a failure criterion, considering temperature and strain ratio was established. Hot working parameters (critical fracture value and critical strain) in deformation could be obtained through the finite element simulation, revealing thatthis newly established failure criterion could accurately predict cracking initiation in compressing deformationof Ti-47Al-2Nb-2Cr alloy ingot.