Ni3Al金属间化合物自蔓延高温合成中的显微组织演变

Microstructural Evolution during Self-Propagating High-Temperature Synthesis of Ni3Al Intermetallic

摘要:

为了研究用Ni粉和Al粉自蔓延高温合成(SHS)Ni3Al过程中的显微组织演变,用燃烧波淬熄法使蔓延的燃烧波自行熄灭,用扫描电子显微镜(SEM)及能谱仪(EDS)观察和分析了淬熄试样中的显微组织,测试了燃烧温度,并用X射线衍射(XRD)分析了合成产物的相组成.结果表明,合成反应开始于Al的熔化,从而使Ni粉粒开始部分溶解,Ni与Al原子间的互扩散导致Ni3Al反应扩散层在未溶解的Ni粉粒表面形成并逐渐增厚.该反应具有不完全性,可能是实验中使用了较粗的Ni粉和Al粉的缘故.

Abstract:

In order to investigate the microstructural evolution of Ni3Al intermetallic from Al and Ni powders during self-propagating high-temperature synthesis (SHS), a combustion front quenching method (CFQM) was used for extinguishing the propagating combustion wave. The microstructures on the quenched sample were observed with scanning electron microscope (SEM) and analyzed with energy dispersive spectrometry (EDS), the temperature of the combustion reaction was tested, and the phase constituent of the synthesized product was inspected by X-ray diffraction (XRD). The results show that the combustion reaction started with melting of the Al particles, and the melting results in partial dissolution of the Ni particles. With interdiffusing between Ni and Al atoms, reaction-diffusing layer of Ni3Al forms on the surface of the undissolving Ni particles and become thicker and thicker continually. Also, the reaction is incomplete, and this is because the coarser Ni and Al powders are used in the present work.