Copper beryllium alloys are used to make clock springs, which are hardly magnetizable and withstand a much higher number of load cycles than steel springs. Ni-Be alloys are very hard and corrosion resistant. Used in surgical instruments. Very pronounced restriction of the γ-phase. With Be it is possible to carry out precipitation hardening, but toughness is reduced in the process. Pronouncedly deoxidizing, considerable affinity for sulphur.