Production of TiAl sheet by cold-rolling

冷轧生产TiAl板

基本信息

批准号：
03555155
负责人：
YAMAGUCHI Masaharu
金额：
$ 6.98万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research (B)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1992
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03555155/
关键词：
Intermetallic compounds TiAl Cold-rolling Recrystallization Lamellar structure Mircostructure control

项目摘要

Polysynthetically twinned (PST) crystals of TiAl with a nearly stoichiometric composition have been grown and rolled at room temperature. The maximum total reduction in thickness which is attainable without fracture depends on lamellar orientation with respect to the rolling plane and rolling direction. When specimens are oriented such that shear deformation parallel to the lamellar boundaries is operative during rolling and its operation causes lengthening of specimens, such specimens can be rolled up to about 50 % reduction in thickness.The recovery and recrystallization behavior of cold-rolled PST crystals of TiAl was also investigated. The change in microhardness was found to occur in two stages regardless of the amount of reduction ; the first sage associated with the decrease in dislocation density and the second stage related with the annealing-out of deformation twins introduced in TiAl lamellae during rolling. However, the recrystallization mode was found to vary depending on the amount of reduction in thickness. In specimens rolled to less than 20 % reduction in thickness, th full recovery in hardness occurs preserving the lamellar structure. A mechanism is proposed to interpret the unusual recrystallization behavior of PST TiAl cold-rolled to less than 20 %.At the later stage of this research, environmental embrittlement was found to occur in PST TiAl. Then, alloying attempts were made to reduce the environmental loss in ductility. The Cr, Mo, V or Mn modified PST TiAl was found to show a small environmental loss in ductility as compared with the binary PST crystals. In particular, the addition of Cr is effective in reducing environmental embrittlement of TiAl. Recently, we confirmed that the Cr-modified PST TiAl can be cold-rolled to 50 w reduction in thickness much more easily than the binary PST TiAl.

在室温下生长并滚动，在三侧的二元组合（PST）晶体已经生长并滚动。在没有断裂的情况下可实现的最大总厚度减小取决于相对于滚动平面和滚动方向的层状方向。当样品定向使与层状边界平行的剪切变形在滚动过程中是可行的，并且其操作会导致标本的延长，也可以将这些标本滚动至厚度下降约50％。还研究了冷滚动的PST PST晶体的恢复和重新安装行为。发现微硬度的变化在两个阶段发生了，无论减少量如何。与脱位密度降低和第二阶段有关的第一个鼠尾草与在滚动过程中在Tial薄片中引入的变形双胞胎退火有关。但是，发现重结晶模式因厚度减小的量而有所不同。在厚度降低到20％的标本中，硬度的全部恢复会保留层状结构。提出了一种机制来解释PST TIAL冷卷至小于20％的异常重结晶行为。在这项研究的后期，在PST TIAL中发现了环境封闭。然后，进行了合金尝试，以减少延展性的环境损失。与二进制PST晶体相比，发现CR，MO，V或MN修饰的PST TIAL显示出延展性较小的环境损失。特别是，CR的添加可有效减少TIAL的环境覆盖。最近，我们证实，与二进制PST TIAL相比，CR修饰的PST TIAL可以更容易将厚度降低至50W。