Effects of Powder Preparation and Sintering Temperature on Properties of Spark Plasma Sintered Ti-48Al-2Cr-8Nb Alloy

• Published in: Metals (Basel ) Vol. 9; no. 8; p. 861
• Main Authors: Wang, Zhenhua, Sun, Haoxuan, Du, Yulei, Yuan, Juntang
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01-08-2019
• Subjects: Aerospace engines; Alloy powders; Alloying; Atomizing; Automotive engines; Ball milling; ball milling process; Bend strength; Composite materials; Cooling; Densification; Density; Diamond pyramid hardness; fine grain strengthening; Fracture strength; Grain size; High temperature; Intermetallic compounds; Mechanical properties; Microstructure; Morphology; Particle size; Plasma sintering; Point defects; Room temperature; Sintering (powder metallurgy); Solid phases; Spark plasma sintering; Spherical powders; TiAl alloy; Titanium alloys; Titanium aluminides; Titanium base alloys; China; Japan
• ISSN: 2075-4701; 2075-4701
• DOI: 10.3390/met9080861

TiAl alloy has become a key element in aerospace and automotive engine development due to its favorable high temperature mechanical properties and low density. In this paper, high performance TiAl alloy was prepared using atomized Ti-48Al-2Cr-8Nb powder by spark plasma sintering. This paper analyzed the variation of density, microstructure, Vickers hardness, and fracture strength of TiAl alloys prepared with spherical pre-alloyed powder (named as SP powder) and pre-alloyed powder after 12 h of ball milling (named as MP powder) at different sintering temperatures. The results indicate that the density, Vickers hardness, and room temperature (25 °C) bending strength of Ti-48Al-2Cr-8Nb alloy sintered using MP powder, are significantly higher than that of TiAl alloy sintered using SP powder. Specifically, the densification temperature of the MP powder sintered specimen is reduced by 100 °C, the Vickers hardness is increased by 15%, and the room temperature bending strength is increased by 51.9% at a sintering temperature of 1250 °C. The microstructure analysis shows that the Ti-48Al-2Cr-8Nb alloy has the best bending strength when it has a fine grain phase structure.