Attempt to ductilize a lightweight intermetallic compound by controlling crystal structure and microstructure

尝试通过控制晶体结构和微观结构来延展轻质金属间化合物

基本信息

批准号：
07805064
负责人：
ITOH Goroh
金额：
$ 1.41万
依托单位：
Nagaoka University of Technology (1996)The University of Tokyo (1995)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

An attempt has been made by modifying crystal structure and microstructure to improve the low room temperature ductility, a serious drawback, of titanium trialuminide (Al_3Ti) base intermetallics which are lightweight and have excellent resistance to high temperature oxidation. Ingots of Al_3 (Ti_<1-y>, X) was produced by argon arc melting, where X=Sc, Er or Lu, and y=0.25,0.5 and 0.75. Each ingot was found to consist of L1_2 and D0_<22> phases at y=0.25 by X-ray diffraction. The ductility (plasticity) of these ingots was assessed by compression test in comparison with that of monolithic Al_3Ti compound composed of D0_<22> single phase and produced in the same way. The results showed that the Sc addition raise the plasticity to about 3% while Er and Lu added alloys have virtually nil plasticity, being the same as the Al_3Ti. The increase in the Sc addition, y=0.5 and y=0.75, brought about further increase in the plasticity to 6% and 11%, respectively. To eliminate the solidification defects and solidification segregation, hot working was applied which had rarely carried out in trialuminide base alloys. Hot isothermal free forging at 1175ﾟC by 55% in a vacuum of about 10^<-3> Pa was found to be made successfully for Al_<74> Ti_<26> and Al_<65> Cr_9 Ti_<26> alloys resulting in a completely recrystallized structure with practically no inhomogeneity arising from solidification. This forging increased the plasticity of the chromium modified alloy from 4% to 9%. An Al_6 TiLi ingot, which was produced by induction melting in an attempt for further reduction in the weight of Al_3 Ti by replacing half of titanium atoms by lithium, was found to contain no L1_2 phase and to have the same tetragonality of the D0_<22> lattice as the Al_3 Ti binary compound.

尝试通过改变晶体结构和显微组织来改善三铝化钛(Al_3Ti)基金属间化合物的室温延展性低这一严重缺陷，该材料具有轻质、耐高温氧化的特点。 -y>，X)通过氩弧熔炼制备，其中X=Sc、Er或Lu，并且y=0.25、0.5和0.75。通过X射线衍射发现每个锭在y＝0.25处由L1_2和D0_<22>相组成。通过与由D0_＜22组成的整体Al_3Ti化合物的延展性（塑性）进行比较来评估这些锭的延展性（塑性）。 > 单相并以相同的方式生产。结果表明，添加 Sc 将塑性提高至 3% 左右，而添加 Er 和 Lu 的合金几乎没有塑性。与Al_3Ti相同，增加Sc添加量，y=0.5和y=0.75，分别使塑性进一步提高至6%和11%，为消除凝固缺陷和凝固偏析，采用热加工。这在三铝化物基合金中很少进行，在1175°C、约10^-3Pa的真空中进行55%的热等温自由锻造。发现可以成功地用于 Al_<74>Ti_<26> 和 Al_<65>Cr_9Ti_<26> 合金，从而产生完全再结晶结构，几乎没有因凝固而产生的不均匀性。这种锻造提高了铬改性合金的塑性。 4%～9%的Al_6 TiLi锭，通过感应熔炼生产，试图通过替代一半的Al_3 Ti来进一步减轻重量。发现锂中的钛原子不含L1_2相并且具有与Al_3 Ti二元化合物相同的D0_22晶格的四方性。