机械合金化制备Ti-Al-Si纳米金属间化合物

4种成分的Ti-Al-Si颗粒T3,T4,T5和T6通过球磨获得非晶.这些非晶在退火时的结构变化分为3个阶段:(1)球磨非晶的部分晶化并产生Ti₅Si₃;(2)其余非晶的完全晶化并依赖于颗粒中Ti和Al的组成产生钛铝金属间化合物,(3)粉末中各相的晶粒长大.晶化反应依粉末成分产生Ti₃Al,TiAl和Al₃Ti.Ti₅Si₃是晶化反应的唯一硅化物.低于800℃退火可获得纳米晶。

Formation of Nanocrystalline Intermetallic Compounds for Ti-Al-Si System by Mechanical Alloying

Amorphous phase was obtained by mechanical alloying of Ti-Al-Si powders with four different composition. The structure evolution of the as-milled amorphous phase during the annealing treatment is classified into three stages:the first is partial crystallization of amorphous phase producing Ti₅Si₃ phase; the second is crystallization of the rest amorphous phase producing the corresponding titanium aluminides according to the relative amount of Ti and Al in the elemental mixture; and the last one is grain growth of all the phase in powders. The crystallization result in formation of Ti₃Al,TiAl and Al₃Ti according the powder composition. Ti₅Si₃ is the only silicide produced by crystallization reaction. The annealing treatment (less than 800℃ for A3, A4 and A5, and 750℃ for A6) shows that the grain size of all the phases fall in nanometer range.