Effect of multi-directional forging on the microstructure and mechanical properties of TiBw/TA15 composite with network architecture

Publication date: 15 November 2017
Source:Materials & Design, Volume 134
Author(s): Rui Zhang, DongJun Wang, ShiJian Yuan
In order to optimize the mechanical properties of the as-sintered TiBw/TA15 composite with a network architecture, multi-directional forging was carried out at near β-transus temperatures. The effects of the multi-directional forging on the mechanical behavior of the composite were investigated. The ultimate tensile strength (UTS) and the maximum elongation exhibited a homogeneous distribution in the forged samples, and at ambient temperature, showed increases of 8.4% and 160%, respectively, when compared to those of the as-sintered composite. The microstructures of samples cut from different positions of the forged workpiece were observed by scanning electron microscopy (SEM). The reinforcement retained the three-dimensional (3D) network in the overall workpiece, although the network units suffered deformation in different directions and were slightly flattened. The microstructures of the matrix were composed of a primary α phase (αp) and transformed β phase (βt) consisting of lamellas/needles of a secondary α phase (αs) and residual β phase. The yield stress (YS) of the composite increased with increasing volume fraction of βt and the proportion of low-angle grain boundaries (LAGBs). The above results revealed that the as-forged microstructure did not show any significant variation with orientation, leading to uniform and improved mechanical properties of the composite.

Graphical abstract

http://ift.tt/2evrbEe