ROLE OF ZIRCONIUM ADDITION ON STABILITY OF UAL3 PHASE IN AL-U SYSTEM

The microstructural changes of Al-22 wt%U and Al-46 wt%U alloys contai ning 3 wt% Zr were investigated after heat treatment at 620 degrees C for 1 to 45 days, Though it is reported that addition of similar to 3 wt% Zr stabilizes the (U,Zr)Al-3 phase at room temperature, the presen t investigation shows that the (U,Zr)Al-3 phase is not stable but slow ly transforms to the U0.9Al4 phase, The high temperature creep curves generated for these ternary alloys showed a wavy pattern which also su ggests that the (U,Zr)Al-3 phase is not stable.