Determination of the (/alpha/sub c//alpha/+/beta/) and (/alpha/+/beta/)/sub b/eta/ phase boundaries in the zirconium-niobium system

The composition Zr-1%Nb is a potential fuel sheathing alloy. Redetermination has been undertaken with a scanning electron microscope fitted with image analysis equipment and an x-ray energy dispersive system. A single alloy containing 2.5%Nb and 0.123% oxygen was used, the specimens having been quenched from temperatures within the (/alpha/+/beta/) region. Image analysis combined with x-ray determination of the /alpha/ and /beta/ phases enabled the (/alpha/+/beta/)/sub b/eta/ phase boundary to be determined within the same samples. Results indicate a maximum niobium solubility in /alpha/-Zr of less than 1%. 32 refs