Evolution of microstructure and mechanical properties of Ti/TiB metal-matrix composite during isothermal multiaxial forging

JOURNAL OF ALLOYS AND COMPOUNDS

卷:770

Article

Ozerov, M.¹  Klimova, M.¹  Sokolovsky, V.¹  Stepanov, N.¹  Popov, A.²  Boldin, M.²  Zherebtsov, S.¹ 

[1] Belgorod State Univ, Belgorod, Russia

[2] Lobachevsky State Univ Nizhni Novgorod, Nizhnii Novgorod, Russia

关键词: metal-matrix composites (MMCs);    precipitation;    sintering;    mechanical properties;    microstructure;    scanning electron microscopy;   

DOI  :  10.1016/j.jallcom.2018.08.215

来源: Elsevier

【 摘 要 】

Mechanical behavior and microstructure evolution of a Ti/TiB metal-matrix composite during multiaxial forging (MAF) at 700 and 850 degrees C and a strain rate 10(-3) s(-1) were studied. The composite was produced via in-situ 3Ti + TiB2 -> 2Ti+2TiB reaction during spark plasma sintering at 1000 degrees C. Mechanical behavior in terms of aggregated sigma-Sigma epsilon curves during MAF at both temperatures demonstrated a pronounced softening following by a steady-like flow stage. Microstructure evolution during MAF at both temperatures was associated with (i) dynamic recrystallization of the titanium matrix and the formation of dislocation-free areas of similar to 1 mu m in diameter and (ii) shortening of TiB whiskers by a factor of similar to 3. MAF at 700 and 850 degrees C to cumulative strain similar to 5.2 resulted in a considerable increase in the low-temperature ductility without substantial loss in strength. Contributions of different strengthening mechanisms into the overall strength of the Ti/TiB metal-matrix composite were discussed. (C) 2018 Elsevier B.V. All rights reserved.

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