<p>The hot deformation behavior of Ti-6Al-4V after diffusion bonding was researched by isothermal hot compression experiment with deformation condition of 700-820&#xa0;°C, 10⁻³-1s⁻¹. The&#xa0;flow&#xa0;curves of the material were analyzed, and the strain-optimized&#xa0;constitutive model was established. The stress was predicted by&#xa0;constitutive model, and the&#xa0;accuracy of the model was verified. Furthermore, a three-dimensional (3-D) hot processing map was developed. The results show that when the temperature decreases or strain rate increases, the peak stress increases. In addition, stresses in various deformation conditions can be precisely predicted with strain-compensated constitutive model, where the correlation coefficients <i>R</i> = 0.988 and average relative errors AARE = 5.07%. The 3-D hot processing map shows that power dissipation efficiency (<i>η</i>) increases when the temperature increases, strain increases, and strain rate reduces. The elevated strain rate or low deformation temperature zone is prone to unstable conditions. By analyzing the 3-D hot process map, the optimized strain rate and temperature range for Ti-6Al-4V hot forming were 0.001-0.014s⁻¹, 770-800&#xa0;°C.</p> Graphical Abstract <p></p>