Aging response and characterization of precipitates in Zr alloy Excel pressure tube material

作者：Sattari M^*; Holt R A; Daymond M R

来源：Journal of Nuclear Materials, 2014, 452(1-3): 265-272.

DOI：10.1016/j.jnucmat.2014.04.038

Precipitation hardening in the Zr-based alloy Excel (Zr-3.5 wt.% Sn-0.8 wt.% Mo-0.8 wt.% Nb) was studied using hardness testing and transmission electron microscopy (TEM). Solution treatment at 890 degrees C, in the alpha(Zr) + beta(Zr) region, and 980 degrees C, in the bZr region, followed by water-quenching and aging resulted in an increase of hardness, of up to 47% compared to the annealed material. The optimum condition for aging heat treatment was found to be 450 degrees C for 1-2 h. The precipitates were observed only in the transformed bZr martensitic phase. Energy dispersive X-ray spectroscopy (EDS) in TEM showed the precipitate composition to be Zr-30 wt.% Mo-25 wt.% Nb-2 wt.% Fe. The crystal structure of the precipitates was determined to be hexagonal with a = 0.294 nm and c = 0.448 nm, i.e. c/a = 1.526.

• 出版日期2014-9