机械球磨与反应烧结制备TiAl基合金

Prepation of TiAl-Based Alloys by Mechanical Milling and Reactive Sintering

研究了机械球磨与反应烧结制备TiAl基合金的工艺 ,结果表明 ,Ti、Al单质混合粉末经机械球磨可得到具有Ti、Al相间层片结构的复合粉 ,且球磨时间越长 ,Ti/Al复合粉的层片结构越薄越均匀。将Ti/Al复合粉压坯在固相下进行扩散反应 ,Ti/Al之间的扩散反应随机械球磨时间的延长而加快 ,且球磨所得到的Ti/Al复合粉在固相下能够完全转变成Ti-Al金属间化合物。反应后得到的Ti -Al金属间化合物经过进一步的高温烧结 ,可以得到近全致密的TiAl基合金 。

The Preparation of TiAl-Based Alloys by Mechanical Milling and Reactive Sintering has been studied in this article. It was revealed that Ti-Al composite powder with lamellar structure of alternative Ti and Al could be obtained from elemental Ti and Al powder mixture by mechanical milling. With the milling time increasing, the lamellar structure of the Ti-Al composite powder became thinner and more uniform. From diffusion reaction performed at solid state of the Ti-Al composite powder billet, it was found that mechanical milling could accelerate the diffusion reaction between Ti and Al, and that the Ti-Al composite powders could be completely transformed into TiAl compounds. By being sintered further at higher temperature, the TiAl-based alloys with near-full density were obtained from the reacted billet, and the typical microstructures of TiAl-based alloys with fine grains and small thickness of lamella were also obtained.