中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
Vol. 22 No. 2 December 2012 |
(National Key Laboratory for Precision Heat Processing of Metals,
Harbin Institute of Technology, Harbin 150001, China)
Abstract:TiB whiskers reinforced Ti6Al4V (TC4) alloy matrix composite (TiBw/Ti64) was fabricated by in-situ reactive hot pressing. The high temperature deformation behavior of the composite was studied by hot compression tests carried out in the temperature range of 900-1100 °C and strain rate range of 0.001-10 s-1. The results show that the flow stress of the composite decreases with the increase of temperature and the decrease of strain rate. At strain rate of 10 s-1, discontinuous yielding followed by flow oscillations can be observed, especially in the β phase region. Constitutive equations were constructed based on the peak flow stresses of the stress-strain curves in α+β phase region and β phase region, respectively. Activation energies for the plastic deformation were also calculated in different temperature ranges according to the constitutive equations, namely, 822.3 kJ/mol in α+β phase region and 209.4 kJ/mol in β phase region. The deformed morphologies of the reinforcement network microstructure and the matrix microstructure greatly depend on the deformation regions and parameters.
Key words: titanium matrix composites (TMCs); TiB whiskers; Ti6Al4V alloy; hot deformation; constitutive equation; network microstructure