Fabrication of large-grained binary stoichiometric Ni3Al
Fabrication of large-grained binary stoichiometric Ni3Al
复制标题
大晶粒二元化学计量Ni3Al的制备
DOI：
10.1016/s1359-6462(98)00392-3
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
O. Umezawa
中科院分区：
文献类型：
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作者：
T. Hirano;M. Demura;E. George;O. Umezawa
二元化学计量比的Ni 3Al由于晶界脆性而难以变形，因此对再结晶知之甚少。到目前为止，仅在韧性合金中研究了再结晶，例如二元富Ni [1-6]和硼掺杂的富Ni Ni 3Al [6-10]。最近，我们报道了通过特殊的浮区法[11-13]，二元化学计量的Ni 3Al的延展性得到了广泛的改善。定向凝固（DS）合金具有柱状晶组织，室温拉伸伸长率大于60%。在这些韧性合金中，可以在不受三元元素影响和不偏离化学计量的情况下研究再结晶行为。这是一个更大的研究的一部分，旨在测量Ni 3Al中的晶界强度，我们需要大的双晶，具有特定的取向差。然而，很难通过从熔体凝固来生长它们，例如通过Bridgman或传统的浮区法，因为二元化学计量的Ni 3Al凝固不一致[16]。两个单晶的扩散结合形成双晶是另一种技术，但它通常会导致质量差的结合界面[18]。因此，我们尝试通过再结晶制备大晶粒板材，并从中切割出双晶拉伸试样。为此，工作的晶粒尺寸应大于5毫米。在本文中，我们提出了一个程序的细节，通过变形和再结晶我们的韧性DS合金和再结晶在二元化学计量的Ni 3Al的一些发现生长大晶粒Ni 3Al。
Little is known about recrystallization in binary stoichiometric Ni3Al because of the difficulty in deformation due to grain boundary brittleness. So far, recrystallization has been studied only in ductile alloys such as binary Ni-rich [1–6] and boron-doped Ni-rich Ni3Al [6–10]. Recently, we have reported an extensive ductility improvement of binary stoichiometric Ni3Al by a special floating zone method [11–13]. The directionally solidified (DS) alloys have a columnar-grained structure and exhibit more than 60% tensile elongation at room temperature. In these ductile alloys it is possible to study the recrystallization behavior without the influence of ternary elements and deviation from stoichiometry. This is part of a larger study aimed measuring the grain boundary strengths in Ni3Al for which we needed large bicrystals, with specific misorientations. However, it is hard to grow them by solidification from the melt, for example by Bridgman or conventional floating zone methods, because binary stoichiometric Ni3Al solidifies incongruently [16]. Diffusion bonding of two single crystals to form bicrystals is another technique but it often results in poor-quality bonded interfaces [18]. Thus, we tried to fabricate large-grained sheet by recrystallization from which bicrystal tensile specimens would be cut. For this to work the grain size should be larger than 5 mm. In this paper, we present the details of a procedure to grow large-grained Ni3Al by deforming and recrystallizing our ductile DS alloys and some findings about the recrystallization in binary stoichiometric Ni3Al.