Mechanically activated effect of friction stir processing in Al-Ti reaction

► Al-Ti reaction kinetics during friction stir processing (FSP) was studied. ► The Al-Ti reaction during FSP was interfacial-reaction controlled. ► The reaction rate constant during FSP was much higher than that during annealing. ► The decrease in activation energy caused by FSP increased the rate constant. ► The effective temperature can show the mechanically activated effect of FSP.