Tensile Behavior of SiC Fiber-Reinforced γ-TiAl Composites Prepared by Suction Casting

Abstract

The process of preparing SiC fiber-reinforced γ-TiAl composites by the conventional methods is difficult and complicated due to the high reactivity, high melting point and poor deformability of γ-TiAl alloys. In this work, suction casting, a promising method for preparing SiC f /TiAl composite, had been attempted. In the process, γ-TiAl alloy melt was introduced rapidly into a mold within pre-arranged fibers that were coated with additional layer of titanium alloy. This simple method successfully prevented serious reactions between the alloy melt and the fibers which remained intact during the solidification process. The interfacial reaction layer was observed by optical microscopy, scanning electron microscopy (SEM). The interfacial reaction products were identified by transmission electron microscopy (TEM). Tensile tests of the matrix alloy and composites were performed at room temperature and 800 °C. The results exhibited that the tensile strength of SiC f /γ-TiAl composite was higher than that of the matrix alloy at both room temperature and 800 °C. At room temperature, tensile strength of SiC f /γ-TiAl composite was increased by about 7% (50 MPa), whereas a double increase in tensile strength 14% (100 MPa) was obtained at 800 °C. The titanium alloy coating on the fiber not only prevented the serious interfacial reaction between the γ-TiAl alloy melt and the SiC fiber, but also played a role in delaying the propagation of cracks in the matrix to the fiber at 800 °C. The fracture mechanism of the composite was analyzed by fracture metallographic analysis.

Wear mechanism of aggregated cBN grains during single-grain ultrasonic vibration-assisted grinding of γ-TiAl alloys

“…Its plate structural components for hypersonic scramjet engines can have a potential for weight reduction of 25%-35% relative to nickel-based alloys. However, its elongation is only 2%-4% at room temperature, and its inherent brittleness limits its application [10][11][12][13]. Meanwhile, the excellent mechanical properties pose a great challenge for machining.…”

A New Method for Preparing Titanium Aluminium Alloy Powder

“…Many researchers have adopted different methods to find an efficient method for producing TiAl-based alloys. The most traditional way is to prepare TiAl-based alloys via casting [22][23][24][25] and cast alloys with different compositions using a vacuum induction melting furnace, centrifuge, hot press, and other equipment. Among them, J Lapin [26] et al prepared the Ti-42.6Al-8.7Nb-0.3Ta-2.0C and Ti-41.0Al-8.7Nb-0.3Ta-3.6C (in at.%) TiAl alloys via the casting method, and studied the effect of adding 2.0C and 3.6C on the properties of the TiAl alloys.…”

Effect of Graphite Powder Addition on Microstructure and Room Temperature Mechanical Properties of Ti-45Al-8Nb Alloys

“…Hence, the addition of particle reinforcement to the TiAl matrix becomes an important means to improve the properties of TiAl alloys. Among the many reinforcing phases, binary ceramic phases are often used to improve the strength and wear resistance of TiAl alloys at room and elevated temperatures due to their higher hardness, specific stiffness, specific strength, and excellent wear resistance [13][14][15][16][17].…”