Influence of Aluminum Content in γ-TiAl with L1_0 Structure during Ordering Processes  

作　　者：Timothée Nsongot1,2 Xiaodong Ni1,3 Guoliang Chen1, Keh-Minn Chang4 1) State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China 2) Faculty of Science, P. 0. Box 69, Brazzaville, Congo 

出　　处：《Rare Metals》2001年第4期230-235,共6页稀有金属（英文版）

基　　金：This work was financially supported by the National Natural Science Foundation of China (No. 59895151-01).

摘　　要：Based on EAM (embedded atom method) interatomic potential, the effect of aluminum content on the type of order-disorder transformation (ODT) and the structure properties (lattice constants, volume, c/a ratio and configu- ration energy) during ordering processes was investigated for γ-TiAI based alloys. Results show that for the alloys with lower than 50%Al (all composition is in atom number fraction), the ODT is the first order transition, and the second order transition for the alloys with equal or higher than 50% Al. The increase of aluminum content results in the critical temperature increasing. The aluminum content has a very little effect on the lattice constants, the volume and the c/a ratio, but has a significant effect on the configuration energy. A metastable disordered state was found for the alloys with less than 50%Al.Based on EAM (embedded atom method) interatomic potential, the effect of aluminum content on the type of order-disorder transformation (ODT) and the structure properties (lattice constants, volume, c/a ratio and configu- ration energy) during ordering processes was investigated for γ-TiAI based alloys. Results show that for the alloys with lower than 50%Al (all composition is in atom number fraction), the ODT is the first order transition, and the second order transition for the alloys with equal or higher than 50% Al. The increase of aluminum content results in the critical temperature increasing. The aluminum content has a very little effect on the lattice constants, the volume and the c/a ratio, but has a significant effect on the configuration energy. A metastable disordered state was found for the alloys with less than 50%Al.

关 键 词：TiA1 order-disorder transformation long-range order 

分 类 号：TG146.2[一般工业技术—材料科学与工程]