摘要
The non-equilibrium microstructure and a new metastable phase of Al-9.6wt%Mg alloy solidified at 6 GPa were studied by optical microscope,differential scanning calorimetry,X-ray diffraction and transmission electron microscope.The results showed that dendrite microstructure was refined,and the solid solubility of Mg inα-Al phase increased greatly.Correspondingly,the lattice parameter ofα-Al phase increased.Al3Mg2 phases disappeared under high pressure solidification.In particular,a metastable phase with small size(20 nm or so)was produced in the alloy,its melting temperature range was 464~518.2℃,which was higher than that of Al3Mg2 phase(453~465℃)under normal pressure.These metastable phases located in the interdendritic position.It was the first time that the metastable phase was found in Al-Mg alloy at a high pressure of 6 GPa.The formation mechanism of the metastable phases was discussed.
基金
This work is financially supported by the Science Foundation of Harbin Institute of Technology(No HIT200229)
