BRUSH WELLMAN I-220 is an instrument grade of beryllium strengthened by a dispersion of 2.2% beryllium oxide maximum. It has a micro-yield strength of 5000 psi minimum. I-220B is manufactured from impact ground powder and therefore is more isotropic than BRUSH WELLMAN S-200E. I-220 is often used as an optical support bench because of its high degree of isotropy and good micro-yield strength. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Be-7. Producer or source: Brush Wellman Inc..