High strength Sn-Mo-Nb-Zr alloy tubes and method of making same
AssigneeAtomic Energy of Canada Limited
InventorBrian A. Cheadle
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Abstract
Tubes for use in nuclear reactors fabricated from a quaternary alloy comprising 2.5-4.0 wt% Sn, 0.5-1.5 wt% Mo, 0.5-1.5 wt% Nb, balance essentially Zr. The tubes are fabricated by a process of hot extrusion, heat treatment, cold working to size and age hardening, so as to produce a microstructure comprising elongated .alpha. grains with an acicular transformed .beta. grain boundary phase.
Claims9
In a method of fabricating extruded alloy tubes from an alloy consisting essentially of Sn 2.5-4.0%, Mo 0.5-1.5%, Nb 0.5-1.5%, O 800-1300 ppm, balance Zr and incidental impurities, in which said alloy is preheated to a temperature in the range 850.degree.-900.degree. C, extruded through a tube forming die, cold worked to size and age hardened by heating at a temperature in the range between 400.degree. and 500.degree. C, the improvement comprising rapidly cooling said extruded tube immediately following extrusion at a rate of at least 30.degree. C per second so as to develop a microstructure comprising hexagonal .alpha. grains elongated in the extrusion direction and an acicular grain boundary phase.
Dependencies are inferred from the claim text.