J. Mater. Sci. Technol. ›› 2024, Vol. 177: 128-132.DOI: 10.1016/j.jmst.2023.09.008

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Simultaneous enhancement of strength and ductility in high Nb-TiAl by Si alloying

Jun Cao, Tielong Sun, Zhichao Guo, Hui Xue, Yongfeng Liang*, Junpin Lin*   

  1. State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China
  • Received:2023-08-03 Revised:2023-08-30 Accepted:2023-09-11 Published:2024-04-01 Online:2024-03-25
  • Contact: *E-mail addresses: liangyf@skl.ustb.edu.cn (Y. Liang),linjunpin@ustb.edu.cn (J. Lin)

Abstract: High-Nb-containing TiAl (High Nb-TiAl) alloys are considered as a new generation of TiAl alloys for applications at higher temperatures. However, their poor room-temperature (RT) mechanical properties, such as near-zero plasticity, significantly limit their applications. To promote the practical applications of high Nb-TiAl alloys, this study investigated the utilization of Si alloying to improve the mechanical properties of these alloys by in situ precipitation of micro-/nanosilicides during the casting process. In particular, S segregation and equiaxed γ grains can improve the plasticity of the alloy, whereas micro-/nanosilicides can strengthen the alloy via the second-phase strengthening effect. The combined effects of S segregation and the ability to generate high-density silicides result in simultaneous enhancement of ultimate tensile strength and plasticity of the alloy at RT and 850 °C.

Key words: High nb-tial, Casting, Mechanical properties, Silicide, Precipitation