Study On The Preparation, Microstructure And Property Of Rapidly Solidified Mg-Zn-Y Alloy

About preparing of high specific strength and corrosion resistance Mg-based alloy and the solidification mechanism research of amorphous or quasicrystal metastable phase on the condition of rapidly solidification, this thesis has proposed firstly a new method that preparing high property bulk Mg-based alloy containing metastable phase. The method contains three preparing steps in vacuum condition,"preparing Mg-based ribbons by melt spinning, preparing powder by milling, preparing bulk alloy by power sintering". On the basis of preparing Mg99-XZn1YX(X=1,2,3), Mg95Zn4.3Y0.7 and Mg82Zn17Y1 master alloy and rapidly solidified ribbons successfully, the effects of composition and cooling rate on solidified structure, mechanical property and chemical stability then had been studied systematically with the aid of TEM, SEM, XRD, XRF, DSC, OM, microhardness analysis and chemical stability analysis experiment, so on. Meanwhile, the solidification mechanism and corrosion mechanisms in different solutions of Mg-Zn-Y on the condition of rapidly solidification (RS) had been discussed in this thesis. Then the bulk sintering Mg82Zn17Y1 alloy had been prepared by milling, forging prepress and sintering, and its mechanical pressure property had also been measured. The main research work and conclusions were presented as follows:(1) Through researching preparing technics, calculating recovery of raw material and optimizing component, Mg-Zn-Y master alloy and RS ribbons of different cooling rate, whose component accords with requiring had been prepared. And the good preparing technics had been proposed in this thesis;(2) It was founded that the phase constitution of RS ribbons with different cooling rates were different from its master alloy in the all composition Mg-Zn-Y alloys that we studied in this thesis. The high cooling rate conduces to get amorphous phase, superfined dispersion MgZnmYn metallic compound andα-Mg(Zn,Y) phase, and thus enhance their microhardness and chemical stability;(3) In RS Mg99-XZn1YX(X=1,2,3) alloys, with the Y content increasing, the volume...