Strengthening effect of in situ TiC particles in Ti matrix composite at temperature range for hot working

In this work, hot-working behavior of Ti matrix composite reinforced with TiC particles was investigated by means of hot compression tests and metallographic techniques. The strengthening effect of TiC particles on flow stress was measured. It was found that there is an about 100 K increase in beta t of the 5 vol.% in situ TiC reinforced Ti-1100 composite compared to that of the monolithic Ti-1100 alloy. The incorporation of TiC particles increased the flow stress significantly. Sharp decreases in flow stress are observed at 10(-1) s(-1) or 10(-2) s(-1) strain rates and 1373 K or 1423 K during hot compression. An improved model was used to characterize the strengthening effect of ceramic reinforcement in term of threshold stress. The calculated values of deformation activation energy and threshold stress vary with test temperature from 1273 to 1423 K, and the threshold stress of the composite decreases from 70 MPa to 18 MPa. Besides the effect of temperature, the great variation of threshold stress may result from the transformation of alpha phase to beta phase partly. (C) 2016 Elsevier Inc. All rights reserved.