MANUFACTURE OF SUPER PLASTIC AL-LI ALLOY

摘要

PURPOSE:To develop the titled alloy having high modulus of elasticity at low density, by heat treating, hot and cold working an ingot of Al-Li alloy under specified conditions. CONSTITUTION:The ingot of Al-Li alloy contg. 1-5wt% Li is held at 400-550 deg.C to homogenize Al and Li and to improve hot workability. Successively, said ingot is hot worked at 300-550 deg.C to a prescribed plate thickness, then said plate is held at 350-550 deg.C for 5-20hr to convert incorporated element to solid solution. In this case, two steps of the first heating at 450-550 deg.C for 0.5-10hr and successive the second heating at 350-550 deg.C for 0.5-50hr are performed, then said ingot is cooled at =30 deg.C/hr rate while being cold rolled at least =30% draft, or 20-60% cold working followed by one time of more low temp. softening annealing at =300 deg.C is performed. Or further said sheet is heated to 350- 550 deg.C at =100 deg.C/hr rate and softened.