When the specimen is loaded beyond its UTS, it a begins to neck (fig2.2) and the elongation is no longer uniform. That is, the change in the cross-sectional area of the specimen is no longer uniform along the length of the specimen but is concentrated locally in a ‘’neck’’ formed in the specimen (known as necking, or necking down) . as the test progresses, the engineering stress drop further and the specimen finally fractures in the necked region. The final stress level (marked by an X in the fig 2.2b ) is known as breaking or fracture stress