机械合金化对TiAl基合金烧结组织的影响

Influence of mechanical alloying on microstructure of sintered TiAl-based alloys

对TiH2-47Al-0.2Si-10Nb和TiH2-47Al-0.2Si-12Nb成分的粉末机械合金化过程进行了研究,并将球磨30 h后的粉末进行放电等离子和真空烧结。借助X射线衍射仪、扫描电子显微镜和透射电子显微镜研究机械合金化对TiAl基合金烧结组织的影响。结果表明,高能机械球磨过程中形成了非晶相及TiAl金属间化合物,球磨30 h后粉末颗粒达到10 nm左右。采用放电等离子和真空烧结均获得了细小、均匀的TiAl和Ti3Al相组织,烧结组织晶粒在1μm左右。

Morphology,structure and phases of TiH2-47Al-0.2Si-10Nb and TiH2-47Al-0.2Si-12Nb powders in the process of mechanical alloying（MA） were investigated.TiAl-based alloys were prepared using the powders milled for 30 h by spark plasma sintering（SPS） and vacuum sintering.Influence of ball milling of the powders on microstructure of the TiAl-based alloys was studied by X-ray diffraction（XRD）,scanning electron microscopy（SEM） and transmission electron microscopy（TEM）.The results show that amorphous phase and TiAl intermetallic compounds formed during the high energy mechanical ball milling,and the particle size reached about 10 nm for the powders after milling for 30 h.The microstructure consisted of fine and homogeneous TiAl and Ti3 Al phases with grain size of 1 μm is obtained for the TiAl-based alloy prepared by SPS and vacuum sintering.