Deformation behaviors and microstructure evolution of TiBw/TA15 composite with novel network architecture

For investigating the deformation characterization of TiBw/TA15 composite with network architecture, the isothermal compression tests within the temperature range of 1193-1313 K and strain rate range of 0.001-1 s(-1) were carried out. The microstructures were observed by scanning electron microscope (SEM) and electron back-scattered diffraction (EBSD) under different deformation conditions. The flow stress curves exhibited various characteristics based on the deformation conditions. The activation energies for deformation of the composite were 654 kJ . mol(-1) in the alpha+beta phase region and 345 kJ . mol-1 in the beta phase region, respectively, which were higher than those of TA15 alloy due to the hindering of TiB reinforcements. The constitutive equation was built by considering the deformation temperature, strain rate and strain. The morphology and fraction of a and 13 phases were also closely depended on deformation conditions. EBSD results showed that TiB whiskers contributed to promoting dynamic recrystallization by providing nucleation sites during the isothermal compression. Additionally, the result of microstructural evolution revealed that the distribution and fragmentation of TiB whiskers were determined by the coordinated deformation of matrix during hot deformation. (C) 2017 Elsevier B.V. All rights reserved.