Structure, phase composition and mechanical characteristics of layered composite materials based on TiB/xTi-Al/α-Ti (x = 1, 1.5, 3) obtained by combustion and high-temperature shear deformation

Abstract

The effect of the ratio of titanium and aluminum in the Ti–Al intermetallic layer on the microstructure, phase composition, and mechanical characteristics of layered composite materials based on TiB/xTi-Al/α-Ti (x = 1, 1.5, 3) is studied systematically. The layered composite materials are obtained by combustion and high-temperature shear deformation. The green sample is a compressed sandwich blank consisting of two Ti–B and Ti–Al powder layers and an α-Ti titanium sheet. The mechanisms of phase and structure formation that occur during synthesis and subsequent high-temperature shear deformation in ceramic and intermetallic layers are described. It is shown that the synthesis between the initial components proceeds according to the reaction-diffusion mechanism. It has been found that the structure, grain size (from 200 nm to 15 μm), phase composition, and mechanical characteristics of the composite can be tuned by changing the initial composition and the delay time before applying external pressure. It is shown that the mechanical characteristics of the resulting composites depend on the location of macrolayers relative to the applied load during high-temperature shear deformation and have the following values: composite surface hardness up to 1800 HV, elastic modulus up to 300 GPa, elastic recovery up to 43, stress intensity factor up to 25.3 MPa m1/2, bending strength up to 650 MPa. The mechanical characteristics of the obtained composites are compared with known analogs, and the advantages are revealed.