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采用透射电子显微分析和力学性能测试方法研究了微量 Sc对 Ti Al合金显微组织和力学性能的影响。结果表明 ,合金的室温抗弯强度和最大挠度均随 Sc含量的增加而下降 ,而合金的高温压缩强度却显著提高。 TEM观察发现 ,Sc的加入使 Ti Al合金中形成大量的呈薄片或颗粒状的 (Sc,Ti) 3 Al相。这种相沿α2 /γ和γ/γT 界面择优分布 ,且与界面位错有交互作用。此种结构组态可能是造成 Ti Al合金的室温性能下降的主要原因。而对于以界面间的滑移为主要变形方式的高温形变 ,由于界面间的滑移受到阻碍作用 ,合金的高温强度得以提高
The effects of trace Sc on the microstructure and mechanical properties of TiAl alloy were investigated by transmission electron microscopy and mechanical properties testing. The results show that both the flexural strength and the maximum deflection at room temperature decrease with the increase of Sc content, but the compressive strength at elevated temperature of the alloy increases significantly. TEM observation showed that Sc addition resulted in the formation of a large number of (Sc, Ti) 3 Al phases in TiAl alloy. Such facies are preferentially distributed along the α2 / γ and γ / γT interfaces and interact with interfacial dislocations. This kind of structural configuration may be the main reason for the decrease of room temperature performance of TiAl alloy. However, the high temperature deformation due to the interfacial slip as the main deformation mode hinders the slippage between the interfaces and the high temperature strength of the alloy is improved