Influence of Ag Addition on Thermal Stability and Thermophysical Properties of Ti-Zr-Ni Quasicrystals

Abstract

We study the effects of Ag addition on thermal stability and thermophysical properties of Ti-Zr-Ni icosahedral quasicrystals. The Ag addition results in increasing the coherence length and thermal stability of the icosahedral phase (i-phase) of the as-cast Ti35.2Zr43.8Ni21 alloy, which are maximized at around 4 at.% Ag addition. Differential scanning calorimetry (DSC) and electrostatic levitation (ESL) experiments reveal that the addition suppresses the i-phase decomposition on heating and cooling. We find that considerable amount of the i-phase remains in the samples processed by radiational cooling in ESL as the Ag concentration increases. These results demonstrate that Ag addition stabilizes the i-phase of the Ti35.2Zr43.8Ni21 alloy. No anomalous effect of Ag addition is found on density and viscosity of the Ti35.2Zr43.8Ni21 liquid.