Elevated temperature deformation behavior of discontinuous-reinforced titanium aluminide matrix composites

A series of Al3Ti- and near-gamma TiAl-matrix discontinuously-reinforced composites have been produced and their elevated temperature flow behavior evaluated. Specifically, steady state compressive flow stress (i.e. maximum flow stress) was determined as a function of temperature (1000, 1100, 1200 degreesC), strain-rate (10(-3), 10(-4) s(-1)), and composite reinforcement loading percentage (30, 40, 50 v%). The experimental results have been used to develop unified constitutive equations for each matrix type that can be used to survey the sensitivity of the respective flow behavior to the independent variables of high temperature wrought processing. The results indicate that while the temperature and strain-rate dependence of flow stress can be described in terms of a traditional Zener-Holloman (temperature-compensated strain-rate) analysis, reinforcement volume percentage may additionally represent a non-traditional but influential independent variable of processing. It is shown that particulate volume loading can be used to positively influence the deformability characteristics of the composite. Crown Copyright (C) 2002 Published by Elsevier Science B.V. All rights reserved.