成分配比对自蔓延高温合成Ni-Al金属间化合物的影响

以镍粉和铝粉为主要原料,采用自蔓延高温合成技术,制备Ni-Al金属间化合物。研究了成分配比对热爆反应的影响,绘制了热爆反应曲线,分析了热爆反应机理及产物的显微组织特征。研究结果表明:成分配比和压坯密度对热爆反应均有不同程度的影响。增加Al含量、加大压坯密度都会缩短热爆起始时间、降低热爆起始温度;反应起始温度低于Ni-Al系的最低共晶温度(640℃)。本文初步确定了Ni-Al系的热爆反应是由固固扩散反应引发的。Ni-32Al的反应产物为均一的NiAl相。

Effect of Chemical Composition on Ti-Al Intermetallic Compounds by Self-propagating High-temperature Synthesis

The self-propagating high-temperature synthesis(SHS) was used to prepare intermetallic compounds using Ni and Al.The influence of different composition on thermal explosion were investigated.The curves of the thermal explosion reaction were drawn.The course and mechanism of thermal explosion and microstructure of SHS product were analyzed.The results show that chemical composition and green density all influence the thermal explosion.The ignition time and temperature of the thermal explosion decrease when increasing content of Al and green density.The ignition temperature of the reaction is lower than the lowest temperature of the Ni-Al.The thermal explosion of Ni-Al system is induced by solid-solid diffusion reaction.The reaction production of Ni-32Al is singular NiAl.