中文摘要：

研究了二级时效对Ti-3Al-7Fe合金组织和硬度的影响。结果表明,合金经889℃×40 min固溶并第一级时效（350℃）＋第二级时效（600℃×8 h）处理后,合金组织中析出的α相弥散分布,未出现与β相混合的片状α相;第一级时效为300℃时,二级时效处理也能使合金组织中析出较多α相,但是α相发生聚集,合金组织不均匀;单级时效处理和第一级时效分别为400、450℃的二级时效处理后,Ti-3Al-7Fe合金组织中在晶界及亚晶界附近出现了夹杂残余β相的片状α相,且合金的组织不均匀。单级时效处理和二级时效处理后,合金的硬度较固溶处理具有较高的硬度。

英文摘要：

The influences of two stage aging on microstructure and hardness of Ti-3AI-7Fe alloy were investigated. The results indicate that α phase in alloy microstructure is disperse distribution, and no lamellar phases mixed with β phases are found in the microstructure after solid solution of 889℃×40 rain and then the first stage aging （350℃）＋second stage aging （600℃×8 h） treatment; when the first-stage aging treatment is 300℃, two stages aging treatment can also make the alloy microstructure separate the α phase, but the aggregation happens, and the microstructure in alloy is not uniform; lamellar et phases mixed with β phases arise near the grain boundary and sub-grain boundary in the mierostructure of Ti-3A1-7Fe alloy after the single stage aging treatment or two stages aging treatment （the first stage aging treatment of 400 and 450℃）, and the microstructure is uneven. The hardness of the alloy is higher than that of the solid solution treatment after single stage aging treatment and two stages aging treatment.