Properties Comparison of Ti-Al-Si Alloys Produced by Various Metallurgy Methods

• Published in: Materials Vol. 12; no. 19; p. 3084
• Main Authors: Knaislová, Anna, Novák, Pavel, Kopeček, Jaromír, Průša, Filip
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 21.09.2019; MDPI
• Subjects: Alloy powders; Aluminum base alloys; Aviation; Cold; Compression tests; Crack initiation; Ductility; Electric arc melting; Fracture toughness; Hardness; Intermetallic compounds; Investigations; Laboratories; Mechanical alloying; Mechanical properties; Melting points; Particle size; Phase composition; Plasma sintering; Porosity; Powder metallurgy; Silicides; Silicon; Sintering (powder metallurgy); Software packages; Solidification; Spark plasma sintering; Titanium alloys; Titanium aluminides; Titanium base alloys; Czech Republic; Netherlands; United States > US; Germany
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma12193084

Melting metallurgy is still the most frequently used and simplest method for the processing of metallic materials. Some of the materials (especially intermetallics) are very difficult to prepare by this method due to the high melting points, poor fluidity, or formation of cracks and pores after casting. This article describes the processing of Ti-Al-Si alloys by arc melting, and shows the microstructure, phase composition, hardness, fracture toughness, and compression tests of these alloys. These results are compared with the same alloys prepared by powder metallurgy by the means of a combination of mechanical alloying and spark plasma sintering. Ti-Al-Si alloys processed by melting metallurgy are characterized by a very coarse structure with central porosity. The phase composition is formed by titanium aluminides and titanium silicides, which are full of cracks. Ti-Al-Si alloys processed by the powder metallurgy route have a relatively homogeneous fine-grained structure with higher hardness. However, these alloys are very brittle. On the other hand, the fracture toughness of arc-melted samples is immeasurable using Palmqvist’s method because the crack is stopped by a large area of titanium aluminide matrix.