TiAl纳米合金的机械活化-放电等离子原位烧结

（Ti-50％（原子分数）AD-10％Al2O3粉体经过球磨的机械活化（MA）后，用放电等离子烧结（SPS）工艺，在烧结的同时进行固化。采用机械活化-放电等离子烧结（MA—SPS）的方法原位烧结制备TiAl—Al2O3块体纳米材料。球磨前后，（Ti-50％（原子分数）AD-10％Al2O3粉体的衍射图（XRD）相似。MA后得到晶粒度〈25nm的纳米粉体，其中Al2O3起到机械活化和细化晶粒的作用，促使粉体快速纳米化。纳米粉体在温度低于800℃、烧结时间〈5min的烧结参数下，烧结成TiAl纳米合金。TiAl纳米合金的微观结构表明，合金有γ-TiAl和α2—Ti3Al双相组织。SPS原位烧结后，得到密度为3．73g／cm^3的（γ＋α2）双相组织，组成相的晶粒度〈130nm。

Fabrication of TiAl nano-alloy by mechanical activation-spark plasma sintering process in situ

Powder of (Ti-50at%Al-10wt%Al2O3 was get through ball milling mechanical activation (MA), and then sintered and concurrently consolidated by using spark plasma sintering (SPS) process. TiAl-Al2O3 bulk nano-material was fabricated using the method of mechanical activation-spark plasma sintering (MA-SPS) in situ. The original and ball milled (Ti-50at% Al)10wt%Al2O3 showed similar X-ray diffraction profiles. After MA, the crystal sizes of nano-powder are less than 25nm. Al2O3 has effect of mechanical activation, while makes crystal fine and accelerates nano-process. The nano-powder was sintered into TiAl alloy on a temperature lower than 800℃, and for a sintering time less than 5min. The microstructure of TiAl alloy contains gamma TiAl and alpha-2 Ti3 Al phase. Through SPS in situ, the final nano-material has dual-phase (γ+ α2 ), and its density is 3.73g/cm3. The crystal sizes of dual-phase are less than 130nm.