The Role of X-Ray Diffraction for Analyzing Zr-Sn-Nb-Fe Alloys as Power Reactor Fuel Cladding

Synthesis of Zr- 1%Nb- 1%Sn- 1%Fe alloy is undertaken in order to develop fuel cladding alloy at high burn-up. Powder specimens of Zr-Sn-Nb-Fe alloy were prepared and then formed into pellets with a dimension of 10 mm in height x 10 mm in diameter using a pressure of 1.2 ton/cm2. The 5 gram green pellets were then melted in an arc furnace crucible under argon atmosphere. The pressure in the furnace was set at 2 psi and the current was 50 A. Afterwards, the ingots were heated at a temperature of 1100 oC for 2 hours and subsequently quenched in water. The ingots then underwent annealing at temperatures of 400 oC, 500 oC, 600 oC, 700 oC, and 750 oC for 2 hours. The specimens were analyzed using X-ray diffraction in order to construct diffractograms. Results of the diffraction patterns were fitted with data from JCPDF (Joint Committee Powder Diffraction File) to determine the type of crystals in the elements or substances. The greater the crystallite dimension, the smaller the dislocation density. Agreeable results for hardening or strengthening were obtained at annealing temperatures of 500 oC and 700, whereas for softening or residual stress at 600 oC and 750 oC. The nucleation of the secondary phase precipitate (SPP) was favourable at annealing temperatures of 400 oC, 500 oC, and 700 oC. For Zr- 1%Nb- 1%Sn- 1%Fe alloy with annealing temperatures between 400 oC to 800 oC, precipitates of Fe2Nb, ZrSn2,FeSn, SnZr, NbSn2, Zr0.68Nb0.25Fe0.08, Fe2Nb0.4Zr0.6, Fe37Nb9Zr54, and ω-Zr were observed. Satisfactory precipitate stabilization was achieved at annealing temperature of 800 oC, growth of precipitates at temperature between 500 oC to 600 oC, and minimization of precipitate size at 700 oC. (author)