The as-cast and heat-treated microstructure of B, Hf, Y micro-alloyed TiAl-based alloy with high Nb content were investigated. The OM observation shows that, the as-cast microstructure of B, Hf, Y micro-alloyed TiAl-based alloy was near lamellar microstructure in which α2/γ lamellar colonies were refined. The XRD analysis shows that, besides α2 and γ phase, β(B2), Y2O3, YAl2 were also included in the as-cast microstructure. The analysis of SEM combined with EDS shows that the β(B2) phase was distributed near the lamellar colonies grain boundaries, granular Y2O3 and YAl2 , and granular or strip boride existed in grains and grain boundaries . After heat treatment at 1260℃ for 20h, at 900℃ for 30min and subsequent air-cooling, the duplex microstructures composed with thin α2/γ lamellar and γ equiaxed axis grains were obtained in the alloy, the β(B2) phase has been basically eliminated, simultaneously the YAl2 has disappeared, and meanwhile Hf-rich Y2O3 and Nb-rich titanium boride phases formed.
WANG Yan-jing, SONG Mei-jin, WANG Ji-jie, DU Xing-hao
. Study on microstructure of multi-component micro-alloying TiAl-based alloy with high Nb content[J]. Journal of Shenyang Aerospace University, 2013
, 30(1)
: 66
-70
.
DOI: 10.3969/j.issn.2095-1248.2013.01.015
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