New biocomposites for alloplastic bone grafts manufacturing gained special attention lately due to advanced designing principles which lead to improved functional characteristics. The hydroxyapatite (HAP, (Ca10(PO4)6(OH)2)) matrix reinforced by micrometric component allows higher biocompatibility related to improved mechanical characteristics [1, 2]. The morphological matching of the alloplastic bone grafts to the genuine bone tissue represents one of the challenges of the tissue engineering research. The porosity of such biocomposites has to match the cortical or trabecular bone tissue. For this purpose, special materials and technologies, related to the powder metallurgy, should include advanced elaboration techniques. The aim of this work is to depict the main physical and chemical processes occurring during the sintering treatments applied for the elaboration of HAP (Sigma-Aldrich, type 1 of av. 200 nm and type 2 of av. 50 μm) based biocomposites reinforced by titanium hydride (TiH2, Sigma-Aldrich, av. 150 μm) powder particles (av. 150 μm). The initial powder mixture contains HAP: TiH2 = 3: 1 ratio [wt.]. The additions of special foaming components (5...25% wt.), working as blowing agents (ammonium bicarbonate and calcium carbonate) as well as TiH2, provide the required porosity, depending on the bone tissue structure to be grafted [3]. The green compacts (90-150 MPa as unilateral compaction pressure) are submitted to the foaming process developing during the first step of the two-steps sintering (TSS) route, up to 9000C, in argon atmosphere. The foaming sequences, corresponding to each foaming agent, have great influence on the final porosity of the obtained biocomposites. The complex processes developing during the foaming reactions are investigated by means of the thermal analysis (TA), simultaneous high temperature thermogravimetry coupled with differential scanning calorimetry (TG-DSC) and Fourier Transform Infrared Analysis (FT-IR).