Relationship between mechanical strength and Young's modulus of porcelain

The relationships between flexural strength σ f and Young's modulus E obtained from the elaboration of several manufacturers data are σ f as 0.87 x 10 -3 E for quartz porcelain and σ f ≈ 1.32 x 10 -3 E for alumina porcelain (σ f expressed in MPa, E expressed in GPa). Data also show that (σ f ) alum.porc. ≈ 2 (σ f ) q.porc and (E) alum.porc. ≈ 1.35 (E) q.porc Nevertheless because of the poor regression coefficients, the above relationships may be used only as a rough approximation for product development in the laboratory and industry.