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用高能球磨机分别对四种成分的Ni50 Al50 x Cox+10%(体积分数,下同)TiC(x=5,10,20)和Ni50 Al45 Co5+20%TiC粉末进行机械合金化,得到原位内生TiC弥散强化的NiAl(Co)纳米复合粉末。结果表明,球磨Ni50 Al45 Co5 10%TiC粉末过程中,爆炸反应机制生成NiAl(Co)和TiC化合物,其中NiAl(Co)化合物晶粒仅为10nm左右,TiC晶粒为35～50nm。但当TiC含量增加到20%时,其爆炸反应起始时间延后20min。同时随着Co含量增加,Ni50 Al40 Co10 10%TiC粉末的机械合金化的产物仍为NiAl(Co)和TiC,但NiAl(Co)化合物的生成机制转变为扩散反应机制。进一步增加Co含量(20%,原子分数)则导致了γ Ni(Al,Co,Ti,C)过饱和固溶体的形成,反应机制仍为互扩散反应。
Mechanical alloying of the four compositions of Ni50Al50xCox + 10% (volume fraction, the same below) TiC (x = 5,10,20) and Ni50Al45Co5 + 20% TiC powder with a high energy ball mill gave the in situ Endogenous TiC dispersion strengthened NiAl (Co) nanocomposite powder. The results show that the NiAl (Co) and TiC compounds are formed by the explosive reaction mechanism during the ball milling of Ni50Al45Co5 10% TiC powder, in which NiAl (Co) compound is only about 10nm in grain size and 35-50nm in TiC grain size. However, when the content of TiC increased to 20%, the initial reaction time of detonation was delayed by 20min. At the same time, with the increase of Co content, the mechanical alloying products of Ni50Al40Co1010% TiC powders are still NiAl (Co) and TiC. However, the formation mechanism of NiAl (Co) compounds changes to diffusion reaction mechanism. The further increase of Co content (20%, atomic fraction) leads to the formation of supersaturated solid solution of γ Ni (Al, Co, Ti, C). The reaction mechanism is still interdiffusion reaction.