Analysis of the Microstructure and Mechanical Properties of Titanium-Based Composites Reinforced by Secondary Phases and B4C Particles Produced via Direct Hot Pressing

Abstract

In the last decade, titanium metal matrix composites (TMCs) have received considerable attention thanks to their interesting properties as a consequence of the clear interface between the matrix and the reinforcing phases formed. In this work, TMCs with 30 vol % of B4C are consolidated by hot pressing. This technique is a powder metallurgy rapid process. Incorporation of the intermetallic to the matrix, 20 vol % (Ti-Al), is also evaluated. Here, the reinforcing phases formed by the reaction between the titanium matrix and the ceramic particles, as well as the intermetallic addition, promote substantial variations to the microstructure and to the properties of the fabricated composites. The influences of the starting materials and the consolidation temperature (900 °C and 1000 °C) are investigated. By X-ray diffraction, scanning and transmission electron microscopy analysis, the in-situ-formed phases in the matrix and the residual ceramic particles were studied. Furthermore, mechanical properties are studied through tensile and bending tests in addition to other properties, such as Young’s modulus, hardness, and densification of the composites. The results show the significant effect of temperature on the microstructure and on the mechanical properties from the same starting powder. Moreover, the Ti-Al addition causes variation in the interface between the reinforcement and the matrix, thereby affecting the behaviour of the TMCs produced at the same temperature.

Pulsed-PTA Preparation of B4C-Based Titanium Matrix Cermet

“…In accordance with this phenomenon, both types of particles with preserved sharp edges and particles with melted, rounded edges are present in the structure. The rounding of the edges cannot be attributed only to the reactions in the solid state, because in the production of TMC by other methods below the melting point B4C, both TiB and TiC are formed too, but the original particles usually remain sharp-edged [42]. When the higher temperature (1200 °C) and time (15min) were used in another method of TMC formation, the particles tend to be less sharped after processing [35].…”

Effect of In-Situ Synthesized Boride Phases on the Impact Behavior of Iron-Based Composites Reinforced by B4C Particles

“…Boriding is a well-known surface hardening process based on the formation of intermetallic Fe 2 B and FeB phases, which occurs as a result of the reaction between iron and boron atoms. Regarding composite materials, their strength and hardness can be improved by the presence of intermetallic phases and compounds [15].…”