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Study on Phase Stability of Light Weight-High Temperature LlィイD22ィエD2-AlィイD23ィエD2Ti Based Alloys.

轻质高温LlyD22-AllyD23-AllyD23D2Ti基合金的相稳定性研究。

基本信息

批准号：
10650695
负责人：
MABUCHI Hiroshi
金额：
$ 2.18万
依托单位：
Osaka Prefecture University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

The intermetallic compound AlィイD23ィエD2Ti is attractive as a potential high-temperature structural material because of its relatively high melting point, low density, and good oxidation resistance. However, it has the low-symmetry tetragonal DOィイD222ィエD2 structure and is very brittle at ambient temperature. One possible approach to ductilize ordered intermetallics with low-symmetry crystal structures is to change their structures to those of higher symmetry. The DOィイD222ィエD2 structure of AlィイD23ィエD2Ti can be changed to the related cubic LlィイD22ィエD2 structure with the addition of a third element, such as Zn, Ni, Cu, or Fe. Also, many studies on the Al-Ti-X (X=Ni, Fe, Cu, Mn, Cr, Ag and Pd etc.) systems have focused on the mechanical properties of the ternary LlィイD22ィエD2 trialuminide compounds. These (Al, X)ィイD23ィエD2Ti compounds will potentially have good oxidation resistance and some ductility because the LlィイD22ィエD2 structure has the requisite five independent slip systems required for … More homogeneous deformation. The ternary LlィイD22ィエD2 compounds, however, are still brittle in tension and/or bending, although they exhibit appreciable compressive ductility at ambient temperature. Recently, much work has been made on the microstrucure, especially second phases and porosity generally induced by a homogenization treatment, and the microstructure, especially second phases and porosity generally induced by a homogenization treatment, and the microstructure-mechanical property relationships of the ternary LlィイD22ィエD2 trialuminide compounds.In the present study, we reported that Ti-9Mn-66Al and Ti-8Cr-67Al alloys with the LlィイD22ィエD2 structure does posses some intrinsic bend ductility at ambient temperature, and Ti-14Mn-61Al and Ti-14Cr-61Al alloys are more ductile in bending, with a plastic strain to 0.4% and 0.9% being recorded, respectively. In these higher manganese and chromium content alloys, no porosity was observed after homogenization. The formation of porosity was caused by Kirkendall mechanism with the second phases solutionized during homogenization treatment. Also recently, the respective bondings and coatings of LlィイD22ィエD2-type and LlィイD20ィエD2 (TiAl) alloys in the Al-Ti-Mn and Al-Ti-Cr systems were carried out to study functionally graded diffusion layers. Thus the microstructure and mechanical properties of the ternary LlィイD22ィエD2 compound are closely associated with the composition of LlィイD22ィエD2 formation and equilibrium second phases surrounding the LlィイD22ィエD2 phase. Less

金属间化合物Al_（23）Al_（23）Al_（23）D_2Ti由于其相对高的熔点、低的密度和良好的抗氧化性而作为潜在的高温结构材料是有吸引力的。然而，它具有低对称性的四氢呋喃D222-D2结构，并且在环境温度下非常脆。使具有低对称性晶体结构的有序金属间化合物延展的一种可能的方法是将它们的结构改变为具有更高对称性的结构。通过添加第三种元素，例如Zn、Ni、Cu或Fe，可以将Al Al 2 O3 D23 Al 2 O3 D2 Ti的D 0 Al 2 O3 D222 Al 2 O3 D2结构改变为相关的立方L1 Al 2 O3 D22 Al 2 O3 D2结构。Al-Ti-X（X=Ni，Fe，Cu，Mn，Cr，Ag，Pd等）合金的研究也取得了很大进展。系统集中在三元L1-D22-D22三铝化物化合物的机械性能上。这些（Al，X）α-D23 β-D2 Ti化合物将潜在地具有良好的抗氧化性和一定的延展性，因为L1 β-D22 β-D2结构具有用于制备所需的必需的五个独立的滑移系统。 ...更多信息均匀变形然而，三元L1-D22-D2化合物在拉伸和/或弯曲时仍然是脆性的，尽管它们在环境温度下表现出可观的压缩延展性。近年来，人们对L1-D22-D22三元系三铝化合物的显微组织，特别是均匀化处理引起的第二相和孔隙率，以及显微组织与力学性能的关系进行了大量的研究。我们报道了具有L1马氏体D22马氏体D2结构的Ti-9 Mn-66 Al和Ti-8 Cr-67 Al合金在环境温度下确实具有一些固有的弯曲延展性，并且Ti-14 Mn-61 Al和Ti-14 Cr-61 Al合金在弯曲中更有延展性，记录到塑性应变为0.4%和0.9%，分别在这些锰和铬含量较高的合金中，均质化后没有观察到孔隙。孔隙的形成是由于均匀化处理过程中第二相固溶而引起的Kirkendall机制。此外，最近，在Al-Ti-Mn和Al-Ti-Cr系统中分别进行了L1-D22-D20-D22-型和L1-D20-D20-D22（TiAl）合金的连接和涂层，以研究功能梯度扩散层。因此，三元化合物的显微结构和力学性能与L1-D22-D22形成的平衡第二相和围绕L1-D22-D22相的平衡第二相的组成密切相关。少