PHYSICAL AND MECHANICAL PROPERTIES OF A TITANIUM-MATRIX Ti-TiN COMPOSITE PRODUCED BY HOT PRESSING
N.Yu. Burkhinova, A.E. Chesnokov, A.A. Filippov, D.V. Dik, K.A. Skorokhod
Khristianovich Institute of Theoretical and Applied Mechanics, Siberian Branch of the Russian Academy of Sciences (ITAM SB RAS), Novosibirsk, Russia
Keywords: hot pressing, titanium, titanium nitride, ultrafine particle, planetary ball mill, structure, compact
Abstract
Results of experiments on the fabrication of a composite material based on PTS-1 titanium with a TiN reinforcing phase at volume fractions of 4, 8, 12, and 21% by hot pressing are presented. A powder mixture of titanium and titanium nitride, mechanically processed in a high-energy planetary ball mill, is sintered at temperatures of 1200, 1300, and 1400°C. The sintered samples are shown to contain primary (α-Ti and β-Ti) and secondary phases (δ-TiN and ε-Ti2N). With increasing titanium nitride concentration, a polymorphic transformation (β ↔ α) occurs, forming the α-Ti-TiN eutectoid. Elevating the sintering temperature is found to increase the grain size of the β-Ti phase by 250%. Owing to the high titanium nitride concentration, the composite structure is transformed, leading to an increase in relative density to 99%, an improvement in material hardness by 97%, and an increase in elastic modulus by 63%.
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