There are different formulations of temperature sensitivity, and different ways to compute it, depending on what your aim is. I'm listing some of the popular ones here, in addition to the nice literature suggested by Prof Hamed Mirzadeh . Please go through this literature and see what suits you best:
(1) To correlate hot deformation with microstructural evolution: Article Flow Softening Index for Assessment of Dynamic Recrystalliza...
(2) To correlate hot deformation behaviour with thermal activation mechanisms (focussing on physical mechanisms): Article Integrated Experimental-Modelling Strategy to Understand Dis...
(3) To assess/predict the development of metallurgical instabilities during deformation: Article Identification of flow instabilities in the processing maps ...