The martensitic transformation in ceramics — its role in transformation toughening

Cluster-assembled cubic zirconia films with tunable and stable nanoscale morphology against thermal annealing

“…1,2 Zirconia finds a wide variety of applications for its mechanical strength and toughness, 3 high chemical resistance, and thermal stability. 4 ZrO 2 films are used for the production of fuel gas sensors, 5 fuel cells, 6,7 and in catalytic applications as supports or active phases.…”

“…[8][9][10] The excellent biocompatibility makes also zirconia a material of choice for orthopaedic prosthesis and dental restorative applications. [11][12][13][14] The above mentioned properties are typical of the tetragonal and cubic high-temperature phases: 1,12 this has stimulated a considerable effort in the characterization of the conditions determining zirconia phase stability and transition. 12,[15][16][17] The high-temperature phases can be stabilized at room temperature by introducing oxygen deficiencies; this is usually obtained by doping zirconia with divalent (Mg 2þ , Ca 2þ ) and trivalent (Y 3þ , Sc 3þ ) cationic species.…”

Peridynamic simulations of the tetragonal to monoclinic phase transformation in zirconium dioxide

“…Both the surface and strain energies are positive whilst the chemical energy is negative. The change in total free energy must be negative for the transformation to proceed (Chevalier et al, 2009;Kelly and Francis Rose, 2002;Platt et al, 2014).…”

“…In engineering ceramics this mechanism is referred to as transformation toughening because of the resulting retardation of crack growth by the tetragonal to monoclinic phase change and its associated increase in volume (Budiansky, 1983;Evans and Heuer, 1980;Kelly and Francis Rose, 2002). Oxides formed on zirconium alloys in autoclave and reactor undergo a transition and acceleration in the corrosion kinetics that has previously been linked with the formation of a network of lateral cracks close to the metal-oxide interface (Bossis et al, 2001;Polatidis et al, 2013;Yilmazbayhan et al, 2006).…”

“…In both cases a key issue is the ingress of oxygen containing species. The tetragonal to monoclinic phase transformation is known to generate cracks (Chevalier et al, 2009;Kelly and Francis Rose, 2002), as a consequence of the ~6% volumetric expansion and ~16% shear strain upon transformation (Platt et al, 2014). Nano-scale cracks associated with this phase transformation have also been observed using transmission electron microscopy (TEM) in oxides formed on zirconium alloys (Bossis, 2002).…”