Relationship between Structure and Properties of Intermetallic Materials Based on γ-TiAl Hardened In Situ with Ti3Al

Abstract

In this work, intermetallic materials based on γ-TiAl in situ strengthened with the Ti3Al phase have been obtained from the initial components of titanium and aluminum under the conditions of free SHS-compression in one technological step and in ten seconds. This method combines the process of the combustion of initial components in the mode of self-propagating high-temperature synthesis (SHS) with high-temperature shear deformation of the synthesized materials. The following initial compositions have been studied (mol): Ti–Al, 1.5 Ti–Al, and 3 Ti–Al. Thermodynamic calculations have been carried out and the actual combustion temperature of the compositions under study has been measured. To increase the exothermicity of the studied compositions, a “chemical furnace” based on a mixture of Ti–C powders has been used, which allows us to increase the combustion temperature and stabilize the combustion front. It has been found that the actual combustion temperature of the selected compositions increased from 890–1120 to 1000–1350 °C. The results of X-ray powder diffraction and SEM are presented, mechanical and tribological characteristics of the obtained materials are measured, and 3D images of wear grooves are given. It has been found that a decrease in Ti molar fraction and an increase in Al molar fraction in the initial mixture lead to an increase in the mechanical (hardness up to 10.2 GPa, modulus of elasticity up to 215 GPa) and tribological characteristics (wear up to 4.5 times, coefficient of friction up to 2.4 times) of intermetallic materials.

Load-Independent Hardness and Indentation Size Effect in Iron Aluminides

“…These distinctive properties endow ICs with a range of unique applications, including hydrogen storage [2,3], catalysis [4,5], shape memory [6,7], superconductors [8,9], and structural applications [10,11]. Structural applications are especially advantageous when high-temperature-resistant components are required due to the high melting and disordering temperatures, high stiffness, and low diffusivity of ICs [10,11].…”

“…These distinctive properties endow ICs with a range of unique applications, including hydrogen storage [2,3], catalysis [4,5], shape memory [6,7], superconductors [8,9], and structural applications [10,11]. Structural applications are especially advantageous when high-temperature-resistant components are required due to the high melting and disordering temperatures, high stiffness, and low diffusivity of ICs [10,11]. Moreover, IC may have also been applicable for ballistic protection due to relatively low density (aluminide ICs), high strain hardening rate, enhanced oxidation and temperature resistance, and some formulations containing minimal or no critical raw materials [12,13].…”

Microstructure and Mechanical Properties of Dual Scaled NbC/Ti2AlC Reinforced Titanium–Aluminum Composite

“…Titanium–Aluminum (TiAl) has attracted the attention of scholars due to its high specific strength and good high-temperature performance [ 1 , 2 , 3 , 4 ]. The urgent problem to be solved for the TiAl alloy is to improve its brittleness at room temperature and enhance the high-temperature strength.…”

Compactability Regularities Observed during Cold Uniaxial Pressing of Layered Powder Green Samples Based on Ti-Al-Nb-Mo-B and Ti-B

“…However, the demand for heat-resistant alloys continues to grow every year, and there are prospects for enhancing the heat-resistant properties of the alloys under development. Presently, a promising approach to increase heat resistance involves reinforcing intermetallic compounds based on titanium aluminides with various strengthening phases [12][13][14][15][16][17][18]. Among the strengthening phases employed, titanium monoboride stands out due to its closely matched coefficient of thermal expansion (7.2 × 10 −6 K −1 ) and excellent chemical and thermal compatibility with the TiAl matrix [19][20][21].…”