Mr. Mohamed Abdel Kawy, research assistant in Casting Technology lab (CMRDI), has been awarded Master degree in Engineering from Faculty of Engineering-Cairo University for thesis entitled “A study of Ti-6 Al-4 V alloy modified by Si-addition”. This thesis was supervised by Assoc. Prof. Khaled M. Ibrahim from CMRDI and Prof. Abdel-Hamed Hussin from Faculty of Engineering-Cairo University. It aims casting Ti-6Al-4V alloy at CMRDI using vacuum induction furnace by adding 0.5% Si, hot swaging at 900 °C followed by solution treatment at 1050 °C and then aging at 500 °C for 24 hrs., and also aims at studying the effect of adding 0.5% Si as a grain refiner and applying different solution treatment processes on microstructure, mechanical properties and corrosion behavior of Ti-6Al-4V alloy. An addition of 0.5%Si to Ti-64 alloy decreases the grain size in the as-cast structure from 630 to 310 µm and reached to 80 µm after applying hot swaging at 900 °C. Finally optimum mechanical properties and corrosion resistance of this alloy was obtained. It could be used in medical implant and aerospace applications.