TiAl＋La有序合金的室温力学性能

ROOM TEMPERATURE MECHANICAL PROPERTIES OF ORDERED TiAl+La ALLOYS

研究了Ｌａ对ＴｉＡｌ合金室温力学性能的影响规律．结果发现，Ｔｉ－４８Ａｌ的强度与延性随Ｌａ含量的增加而增加，并分别在１０和０．２ａｔ－％Ｌａ含量处达到最大值，值得注意的是加Ｌａ的ＴｉＡｌ合金的最佳延性要比ＴｉＡｌ高出一倍多．经分析观察表明，Ｌａ可使ＴｉＡｌ显微组织均匀细化，并形成Ｌａ２Ｏ３粒子，降低了基体中的氧含量，是ＴｉＡｌ合金性能得到改善的原因。而过多的Ｌａ导致在ＴｉＡｌ中形成粗大的氧化物粒子和气孔，使其性能恶化．

The strength and ductility of Ti-48Al may be improved by adding certain amount of La and approached to optimal values with increasing to 1.0 and 0.2 at.-% La respectively.It seems to be noticeable that the optimal ductility of TiAl alloy containing La is higher beyond twice than that free from La.Observations showed that the improvement may be caused by the La due to homogenize and refine the TiAl microstructure,to form La2O3 particles and to reduce O2 content in matrix. However,excess La addition would result in forming coarse oxide particles and some pores,thus its mechanical properties deteriorate.