机械合金化对TiAl基合金烧结组织的影响

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。     

Mechanical alloying and characteristics of spark plasma sintering of Ti-A1 composite powders

The mechanical alloying process of Ti-Al composite powders were carried out by use of high energy ball-milling machine. Structure variations of powder mixtures during mechanical alloying and characteristic of spark plasma sintering were investigated. The results show that during milling, TiAl, Ti3Al and Ti2Al phase intermetallic compounds are formed, simultaneously with powder refinement for the （TiH2-45Al-0.2Si-SNb） and （TiH2-45Al-0.2Si-7Nb） mixtures. The particle sizes of two powder mixtures are less than 300 nm after milling for 30 h. Sintering process of the milled powder can be completed in a short time by spark plasma sintering, and the sintering microstructure is composed of fine and homogeneous TiAl and Ti3Al phase.