Effect of Titanium Diboride Content on Basic Mechanical Properties of Composites Sintered from TiH2 + TiB2 Powder Mixtures

The paper examines how the titanium diboride content of the starting TiH2–TiB2 powder mixture influences basic mechanical properties of the resultant sintered composites in tension and compression tests. The porosity of the compacts sintered at 1250°C increases with greater titanium diboride content of the starting mixture, which is associated with the Frenkel effect that occurs in the sintering process. Although the porosity somewhat increases, the strength, hardness, and elastic modulus in tension become higher when 5% TiB2 powder is introduced into the charge. These characteristics however decrease when the high-modulus component increases to 10% in the charge. The ductility of the sintered alloys monotonically reduces with higher boride content. The yield point and compressive strength monotonically increase with higher TiB2 content of the charge, despite greater porosity. This occurs because porosity has a significantly weaker effect on the strain resistance of the sintered Ti–TiB composites in compression than in tension.