Pore formation and compressive deformation in porous TiAl–Nb alloys containing directional pores
Pore formation and compressive deformation in porous TiAl–Nb alloys containing directional pores
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DOI：
10.1016/j.matdes.2013.02.031
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发表时间：
2013-08
影响因子：
8.4
通讯作者：
F. Yang;M. Tane;Junpin Lin;Y. H. Song;H. Nakajima
中科院分区：
文献类型：
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作者：
F. Yang;M. Tane;Junpin Lin;Y. H. Song;H. Nakajima
多孔Ti-xAl-8 Nb（x=45、48和49at%）合金（即，金属间化合物TiAl-Nb化合物），其具有沿沿着单个方向取向的圆柱形孔，通过在氢气和氦气气氛中的单向凝固制备，同时利用合金的液相和固相的氢溶解度的差异。合金的显微组织和孔隙形貌表明，合金中孔隙的形成与其凝固过程密切相关。在x= 45at%的合金中，初生β（bcc）相具有较高的氢溶解度，抑制了凝固过程中气孔的形成。而当x= 49at%时，初生β相的形成受到抑制，导致沿凝固方向形成沿着的细长孔。热处理后，多孔TiAl-Nb合金呈现由α2-Ti 3Al和γ-TiAl相组成的全层片结构。这些具有层状结构和定向气孔的多孔TiAl-Nb合金具有与气孔方向平行的上级压缩性能。
Porous Ti–xAl–8Nb (x=45, 48, and 49at%) alloys (i.e., intermetallic TiAl–Nb compounds) with cylindrical pores oriented along a single direction were prepared via unidirectional solidification in a hydrogen and helium gas atmosphere, while making use of the differences in the hydrogen solubilities of the liquid and solid phases of the alloys. The microstructures and pore morphologies of the alloys revealed that pore formation in the alloys was closely related to their solidification processes. In the case of the alloy with x=45at%, a primary solidified β (bcc) phase with high hydrogen solubility suppressed the formation of pores during solidification. On the other hand, in the case of the alloy with x=49at%, the formation of the primary β phase was suppressed, leading to the formation of elongated pores along the solidification direction. After being heat treated, the porous TiAl–Nb alloys exhibited a fully lamellar structure composed of α2-Ti3Al and γ-TiAl phases. These porous TiAl–Nb alloys with lamellar structures and directional pores exhibited superior compressive properties parallel to the direction of the pores.