Briefly discuss how plastic deformation occurs in crystalline materials. discuss the important methods of strengthening used in (i) cold rolled 1018 steel, (ii) 2024al alloy in t6 heat treated condition, (iii) brasses, and (iv) quenched and tempered 1045 steel.

At steady state, air at 200 kpa, 325 k, and mass flow rate of 0.5 kg/s enters an insulated duct having differing inlet and exit cross-sectional areas. the inlet cross-sectional area is 6 cm2. at the duct exit, the pressure of the air is 100 kpa and the velocity is 250 m/s. neglecting potential energy effects and modeling air as an 1.008 kj/kg k, determine ideal gas with constant cp = (a) the velocity of the air at the inlet, in m/s. (b) the temperature of the air at the exit, in k. (c) the exit cross-sectional area, in cm2