Zircadyne® alloys are composed of 95.5% to 99.2% zirconium and hafnium with a maximum hafnium content of 4.5%. Zircadyne mill products are available in two chemical grades each sharing excellent corrosion resistance and also having slightly different physical and mechanical properties. Zircadyne 702 Zirconium is commercially pure. Zircadyne 705 zirconium is alloyed with niobium to increase its strength and improve its formability. Table 1 shows the chemical composition of Zircadyne alloys. The presence of hafnium in Zircadyne alloys does not significantly influence the physical, mechanical, or corrosion properties.

Zirconium, a reactive metal, has a high affinity for oxygen that results in the formation of a protective oxide layer in air at room temperature. This protective oxide gives Zircadyne alloys their superior corrosion resistance and this oxide layer can be enhanced through a heat treating process. A properly formed enhanced oxide layer serves as an excellent bearing surface against a variety of materials, imparts impressive erosion resistance in high velocity systems, and can improve the corrosion resistance in certain aggressive environments.

Zircadyne alloys exhibit good ductility even at cryogenic temperatures and good strength comparable with other common engineering alloys. In addition to being integral to the oxide layer, oxygen is an interstitial strengthening element in Zircadyne alloys. Zircadyne alloys do not exhibit a low temperature ductile to brittle transition.