镧对TiAl3金属间化合物显微组织及力学性能的影响

Effect of Adding La on the Microstructure and Mechanics Properties of TiAl3 Intermetallics

摘要:

采用机械合金化及退火工艺制备镧改性的TiAl3金属间化合物。通过X射线衍射、粒度分析、透射电镜、硬度、延伸率及断裂韧性研究镧对TiAl3显微组织以及室温力学性能的影响。结果表明：添加镧可使DO22型TiAl3的晶体结构向有序立方L12型转化，断裂韧性最大提高143.75%，可有效改善其室温脆性。镧的加入使TiAl3的硬度有所损失，试样的室温维氏硬度为3450~3500 MPa

关键词:镧;L12-TiAl3;机械合金化;断裂韧性

Abstract:

La-modified TiAl3 intermetallics were prepared by combined processing of mechanical alloying and annealing. The effects of adding lanthanum on the microstructure and mechanical properties of TiAl3 were investigated by XRD, particle size and distribution analysis, TEM, the tests of hardness, elongation and fracture toughness. The results show that adding trace element lanthanum can make the DO22 type TiAl3 crystal structure transform into the related cubic L12 structure. The fracture toughness of alloys modified by adding La can be increased by 143.75%. However, the Vickers hardness of the Al-Ti-La powders is smaller than that of the Al-Ti powders

Key words:lanthanum; L12-TiAl3; mechanical alloying; fracture toughness