**2. Materials and methods**

#### **2.1 Materials**

In order to elaborate Al2O3-TCP, the materials used were commercial Al2O3 (Riedel-de Haёn, purity >98%) and synthesized tricalcium phosphate powders.

The β-TCP powder was synthesized by solid-state reaction from calcium phosphate dibasic anhydrous (CaHPO4) and calcium carbonate (CaCO3). Stoichiometric amounts of high purity powders, CaCO3 (Fluka, purity ≥98.5%) and CaHPO4 (Fluka, purity ≥99%) were sintered at 1000°C for 20 hours to obtain the β-TCP according to the following reaction [18]:

Synthesized Tricalcium phosphate was introduced with α-Alumina powders. The approximate representatives Al2O3-TCP were {90 wt.%, 10 wt.%}, {80 wt.%, 20 wt.%}, {60 wt.%, 40 wt.%} and {50 wt.%, 50 wt.%}.

It is worth mentioning that the size of particles of each powder was measured (2.53 μm for Al2O3 and 2.79 μm for TCP).

As starting materials, calculated quantities of The β-TCP and Al2O3 powder were mixed by homogeneous mixing in a mortar and milled in absolute ethanol and treated with an ultrasound machine for 20 min. After milling these powders, the mixture was dried at 80°C for 24 hours to eliminate the ethanol. After drying, mixtures powders thus prepared were molded in a metallic cylinder mold having a diameter of 30 mm and a thickness of 5 mm and uniaxially pressed at 67 MPa. A crack "2a" of 12 mm was added to the CSTBD specimens were considered for each compacted specimens. The crack of the CSTBD specimens was added by a specific metal mold (**Figure 1**). At least six specimens were tested under each test condition.

Finally, the specimens were sintered at 1600°C for 1 hour in a vertical programmable muffle furnace (Pyrox 2408) and were heated and cooled at a rate of 10° C min�<sup>1</sup> and 20°C min�<sup>1</sup> , respectively.

On the other hand, one side of each fracture sample has been sprayed with black then white paint in order to form the speckle pattern that will be used by the Digital Image Correlation (DIC) technique.
