THE HEAT TREATMENT, TRANSFORMATION REACTIONS, AND MECHANICAL PROPERTIES OF SOME HIGH-STRENGTH ZIRCONIUM-BASE ALLOYS

Zirconium alpha-beta alloys were found to respond to solution and aging heat treatmeats very similarly to titanium alpha-beta alloys. A zirconium-5 wt.% molybderum-2 wt.%fl tin alloy was heat treated to a L68,500-psi tensile strength and a 153,500-psi yield strength, with 11.5% elongation in 1 in. In addition, a zirconium-5 wt.% niobinm-2 wt.% tin alloy was heat treated to a 190,500-psi tensile and a 178,000-psi yield strength, with 2% elongation. The transformations that occur upon aging these alloys may be represented as follows: beta deg C was con- omega + beta /sub r/ deg C was con- alpha + beta / sub u/and alpha deg C was con- alpha + beta /sub r/. Preliminary elevated-temperature propenties were very good. The zirconium-5 wt.%fl molybderum-2 wt.%fl tin alloy solution treated at 1525 F and aged 8 hr at 1000 F was evaluated for tensile strength and 100-hr rupture life at 840 F. The tensile strengh, yield strength, and elongation were 111,000 psi, 84,500 psi, and l2%fl, respectively. The 100-hr rupture strength was about 95,000 psi. (auth