Abstract : As a revision to Contract no. W56HZV-05-0721 (WD-FH-0004), this task was added to the current project for the purpose of performing material characterizations and developing Johnson-Cook (J-C) strength and damage constants of friction stir welded (FSW) ballistic joints. These material constants will be used by the government for ballistic blast and other types of modeling and simulation, and will be included in the Elastic Plastic Impact Code (EPIC) library. This report describes the welding and machining processes used to manufacture the material test specimens used for the J-C material characterization tests and provides the results of metallurgical analysis for the FSW joint of each selected armor material.