BERYLLIUM CASTING. Interim Technical Report No. 8, Phase II for June 18, 1960 to September 17, 1960

An evaluation of alloy additions of lanthanum and zinconium is described. Increasing columnar grain refinement results with increasing alloy additions of lanthanum. Zirconium as an alloying grain refiner has an optimum concentration of 0.40 to 0.60 wt.% for maximum columnar grain refinement. The step castings show the reduction of coluumar grain size by increasing the cooling rate. Heat treating with prior cold reduction to promote recrystallization of the cast structure has yielded tentative relation for recrystallization time and temperature for 10% cold bare rolled cast beryllium. A trend has been observed with an optimum per cent cold reduction for a given heat treatment for maximum grain refinement. These tentative results require more work to definitely establish certain points. (auth)