Effect of temperature, strain rate and grain size on the mechanical response of Ti3SiC2 in tension

Tensile, relaxation and cycling loading-unloading tests indicate that the mechanical response of Ti3SiC2 has a strong dependence on temperature and strain rate, but a weak dependence on grain size. Loading at low temperatures, and/or high strain rates, results in elastic and anelastic deformation, followed by brittle fracture. Anelastic deformation in this regime can be attributed to the easy glide of dislocation into pileups during loading, and their run back during unloading. At high temperatures (approximate to1100-1200degreesC), and/or low (<10(-5) s(-1)) strain rates, the response is plastic. The resulting strain is elastic, anelastic and plastic. Even at 1200degreesC, intense stress-relaxation processes are observed, and a sizable fraction (approximate to13%) of the strain is anelastic. At intermediate temperatures and strain rates (transition regime) the mechanical response is controlled by simultaneous damage formation (microcracking) and localized plastic deformation. Combining the results obtained in this work with previous results, viz. tensile creep and strain transient dip tests, a deformation map that takes into account temperature, grain size and strain rate is defined. (C) 2002 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.