Environmental Stability and Residual Stresses in Zirconia Femoral Head for Total Hip Arthroplasty: In Vitro Aging versus Retrieval Studies

Figure 4

Raman spectroscopic data for the Head (I) surface showing the evolution of transformation-induced residual stresses in tetragonal (a) and monoclinic phase (b) as a function of the aging time. The equilibrium stress obtained according to (3) is also plotted in (c).

(a) Tetragonal phase

(b) Monoclinic phase

(c) Equilibrium