1. Prove mathematically that in a uniaxial forming process, like wire drawing of a ductile,strain-hardening material, such as, AA 6000 Aluminum alloy, the true strain e, at the onset of Tensile Plastic Instability equals in magnitude to the strain-hardening exponent, of the work piece material. (10 points). Hint: Use Ludwick's equation and the Forcevs. True-strain curve.

Fig: 1