Influence of crystallographic compatibility on phase transition in the ceramic YTaO4-ZrHfO4 systemMonday (17.06.2019) 14:15 - 14:30
When shape memory properties are desired for applications in environments with harsh chemical conditions and high temperatures, ceramic materials seem like a good choice. However, those tend to fail after only few load cycles and require fairly high stresses for relatively little strains. Some promising hints for a good shape memory ceramic (SMC) have been found in the Y2O3-Ta2O5-ZrO2-HfO2 system. The materials form a variation rich monoclinic low temperature phase as it is seen in traditional shape memory alloys which can, in suitable temperature regimes, be utilized for superelasticity and shape memory effects. The crystallographic background based in compatibility theory as well as its performance in terms of mechanical and thermal cycling with respect to concentration dependent transition temperatures and reduced thermal hysteresis as low as 75 K compared to >200 K for pure ZrO2 is analyzed and its future potential presented.