E Farid - MSc student, Department of Material Science and Engineering, Hamedan University of Technology, Hamedan, Iran
A Momeni - Assistant Professor, Department of Material Science and Engineering, Hamedan University of Technology, Hamedan, Iran
E Khademi - Assistant Professor, Department of Robotics, Hamedan University of Technology, Hamedan, Iran

Friction stir processing (FSP) is one of the newest methods for microstructural refinement of metals. In thepresent study, FSP was performed on Ti-6Al-4V alloy using a tungsten carbide tool with rotation speed of 1250 rpmand the effect of travers speed ranging from 8 to 40 mm / min, on mechanical properties and microstructure of theprocess are investigated. The microstructural investigations showed that FSP leads to the initial structure hastransformed from equiaxed alpha, to Grain boundary, Acicular and martensite alpha in the fine beta grain structure.Micro hardness tests results show that the highest hardness was in stir zone and the lowest in the HAZ zone.

Friction Stir Processing, Fine the grain size, Ti-6Al-4V Alloy, Tensile test, Micro hardness