Refinement of lamellar structures in Ti-Al alloy
Refinement of lamellar structures in Ti-Al alloy
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DOI：
10.1016/j.actamat.2016.11.045
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发表时间：
2017-02
期刊：
影响因子：
9.4
通讯作者：
Daixiu Wei;Yuichiro Koizumi;M. Nagasako;A. Chiba
中科院分区：
文献类型：
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作者：
Daixiu Wei;Yuichiro Koizumi;M. Nagasako;A. Chiba
Ti-40 at.% Al过饱和α2-Ti 3Al晶粒的热变形行为及细化在应变速率为1 s−1的条件下，对铝合金在单一α-hcp相区进行压缩试验。颗粒显着细化和均匀的热压缩，产生超过50%的圆柱形样品的高度减少。在1473 K下压缩70%后，晶粒由660 μm细化到3.56 μm，并引入了高密度位错。此外，由于Al过饱和α2-Ti 3Al晶粒的细化和热压缩引入的高密度位错，压缩试样时效后形成的片层组织明显细化。此外，α2-Ti 3Al基体中位错的分布和密度也影响着片层的形貌。70%压缩试样经1073 K × 10 ks时效后形成了平均片层团尺寸为4.1 μm、平均片层间距为25 nm的超细片层组织，并沿片层团边界形成了大量沿着分布的超细γ晶粒。
The hot deformation behavior and refinement of Al-supersaturated α2-Ti3Al grains of Ti-40 at.% Al alloy were investigated by compression tests in a single α-hcp phase region at a strain rate of 1 s−1. Grains were significantly refined and homogenized by hot compression that produced more than a 50% reduction in the height of cylindrical samples. The grains were refined from 660 μm to 3.56 μm by 70% compression at 1473 K, and high densities of dislocations were introduced. In addition, the lamellar structures formed after subsequent aging of the compressed samples were significantly refined, owing to the refinement of Al-supersaturated α2-Ti3Al grains and the introduction of a high density of dislocations by hot compression. Moreover, the lamellar morphologies were affected by the distribution and density of dislocations in the α2-Ti3Al matrix. Ultra-fine lamellar structures with an average lamellar colony size of 4.1 μm and an average lamellar spacing of 25 nm were formed in the 70% compressed sample after aging at 1073 K for 10 ks In addition, a large number of ultra-fine γ grains were formed along the lamellar colony boundaries.