Combustion Synthesis Preparation And Characterization Of Mg/Mg₂Si Composite Material

Intermetallic compound Mg₂Si is fit for moderate and high temperature structural material and hopeful to be used in aeronautics, astronautics and automotive industry for its virtues such as low density, high melting point and high specific strength and so on. But it is very difficult to process because of its intrinsic embrittlement. So the research of improving the brittleness of Mg₂Si has a far importance at not only theoretical side but also practical application side.In this paper, Mg/Mg₂Si composite material which was based on intermetallic compound Mg₂Si and added with tenacious phase-Mg was synthesized by self-propagating combustion mode and explosion mode respectively and researched. In ideal state the relationships of preheat temperature, adiabatic temperature and quantity of diluents, adiabatic temperature were calculated. The results show that with the increasing of preheat temperature the adiabatic temperature of Mg-Si system increases and reaches a flat roof; with the increasing of quantity of diluents the adiabatic temperature decreases, so does the flat roof .The influences to compactness of samples of the influential factors such as preheating temperature, pressure of green compact, powder size of Mg, Mg(wt)% in the progress of Mg/Mg2Si composite synthesized by self-propagating combustion mode and the influential factors such as preheating velocity pressure of green compact, powder size of Mg, Mg(wt)% in the progress of Mg/Mg₂Si composite synthesized by explosion mode were discussed. The investigation indicats that the influences of every factors are different on samples' compactness. But there is a regulation that is influence of powder size of Mg>influence of preheating velocity(preheating temperature)>influence of pressure of green compact.By analysis of valence electronic structure, it is found that the amount of the valence electron pairs on the strongest bond of Mg2Si unit cell is intervenient between Mg and Si. The density and the melting point of Mg2Si is also intervenient between Mg and Si, which is relative with the calculate result.