Microstructure control and dynamic recrystallization behavior analysis in hot forging of metastable beta Ti-5Mo-4Fe alloy.

Titanium alloys, which are widely used in aerospace materials, have low thermal conductivity, leading to difficulty in hot forging. In particular, process parameters such as deformation temperature and strain rate significantly contribute to the deformation behavior of the microstructure and directly affect the mechanical properties. Therefore, to evaluate the formability by simulating a hot forging process that forms uniform and fine grains, the Ti-5Mo-4Fe alloy was tested using hot compression at deformation temperatures of 700–950 ℃ and strain rates of 0.001–1/s. Depending on the process parameters, the alloy exhibited microstructural changes such as lamellar kinking, dynamic spheroidization, dynamic recrystallization, and grain growth. Additionally, by easy dynamic spheroidization and dynamic recrystallization of the fine initial lamellar structure by the addition of Fe, grains with an average size (diameter) of 7 μm or less were formed after hot compression. The study identified the conditions of 750 ℃, 1/s and 900 ℃, 1/s as the optimal process conditions, under which the dislocation density was effectively resolved and a number of fine grains were observed. • A study on influence of several hot forging process variables in metastable Ti-5Mo-4Fe alloy. • Effect of deformation temperature, strain rate on the occurrence of two recrystallization mechanisms (CDRX, DDRX). • Dynamic recrystallization with grain size distributions ranging from 1 to 10 um and from 10 to 100 um. [ABSTRACT FROM AUTHOR]