A STUDY ON ALUMINIDE COATINGS ON TiAl ALLOYS BY PACKCEMENTATION METHOD

作     者：C.G. Zhou, H.B. Xu and S.K. Gong (Department of Materials Science and Engineering, Beijing University of Aeronautics and Astronautics,Beijing 100083, China) K. Y. Kim (Department of Materials Science and Engineering, Pohang University of Science and Techn 

出 版 物：《Acta Metallurgica Sinica(English Letters)》 (金属学报（英文版）)

年 卷 期：2000年第13卷第6期

页      面：1148-1154页

核心收录：

学科分类：08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

基　　金：The National Natural Science Foundation of China The Korea Science and Engineering Foundation 

主　　题：TiAl alloying element pack cementation aluminizing 

摘      要：The halide-activated pack cementation method is utilized to deposit aluminide coat- ings on TiAl alloys. Emphasis is placed on the effect of alloying elements on the aluminizing behavior of TiAl alloy. The addition of a small amount of Nb or Cr in the TiAl improves significantly the aluminizing kinetics of TiAl alloys by increasing the solid-state division of Al through the formation of stable TiAl3 layer. The TiAl3 layer formed on the TiAl alloyed with Nb or Cr has better toughness than the TiAl3 formed on the non-alloyed TiAl. The reason for better toughness of the coating formed on TiAl is that partial TiAl3 with tetragonal structure was changed to high symmetry cubic L12 structure since Nb or Cr was dissolved into TiAl3. The TiAl3 layer formed on the TiAl alloyed with Nb or Cr has much better oxidation resistance than the TiAl3 layer formed on the non-alloyed TiAl. It is attributed to change in the crystal structure of TiAl3 from the brittle tetragonal DO22 to the ductile cubic L12 by addition of small amount of Nb or Cr.