Enhanced Fracture Toughness and High-Temperature Strength of Directionally Solidified Mo-XC Alloys

Abstract

The present article focuses on refractory metals strengthened by ceramic phases to improve the mechanical properties at ambient temperatures as well as at high temperatures. In this work, near-eutectic, directionally solidified (DS) Mo-34TiC and Mo-27ZrC alloys are investigated with regard to their microstructures, fracture toughness at room temperature and compressive strength at high temperatures. Superior fracture toughness as well as competitive strength compared with other Mo-XC composites are achieved. Compressive tests up to 1000 °C on longitudinal and transversal specimens show the significant impact of the anisotropy on the strength.

Keywords

• directional solidification
• zone melting
• Mo-TiC
• Mo-ZrC
• eutectic colonies
• lamellar microstructure