Microstructure, High Temperature Strength and CO-Gas Emission of Liquid-Phase Sintered and Forged Low Oxygen TiC-ZrC-Mo Alloy
Hitoshi AOYAMA, Shinichi YAMAMOTO, Yukio MIYASHITA and Yoshiharu MUTOH
Abstract:A new process for producing 0.5%Ti-0.07%Zr-Mo alloy with low-oxygen content and high strength at elevated temperature was successfully developed, where the mixed TiC, ZrC and Mo powders were liquid-sintered without addition of C or Mo2C as aids for degassing of oxygen. The developed new TiZrC alloy indicated high strength at elevated temperature even under low forging rate compared to the conventional TiZrO alloy and commercial TZM alloy. Ti and Zr carbides with high melting points were precipitated along Mo grain boundaries in TiZrC alloy, while Ti and Zr combined oxide particles with low melting points were precipitated in Mo grain boundaries in TiZrO alloy. The high strength at elevated temperature in TiZrC alloy will result from the grain boundary precipitation of the carbides, which suppressed grain growth and were stable at elevated temperature. The amount of CO gas emission from the TiZrC alloy were almost equivalent to that from the conventional TiZrO alloy during heating in X ray tube. Key Words:Mo alloy, TiC-ZrC-Mo alloy, High temperature strength, CO gas emission, X ray tube anode