Mg/Al合金粉末热压烧结中相变扩散过程研究

利用OLYMPUS GX71金相显微镜及EDS对Al-15％Mg热压烧结样品进行金相显微组织观察与成分分析，探讨烧结过程中组织演变过程。实验结果表明：热压烧结过程中两种粉体发生互扩散，首先在Mg颗粒边缘形成γ（Al12Mg17）相，而后随扩散的进行γ相转变为β（Al3Mg2）相，Mg颗粒由外向内不断的形成γ相，而后不断的转变为β相，直到全部生成β相。随温度的降低，β相会以极其细小的颗粒形式析出；利用真空热压烧结方法在420℃，150Mpa下保压3—4h进行固相烧结获得密度低于2．5g／cm^3致密度达98％以上的Al—15％Mg合金。

Research on phase transition of Al/Mg powder during sintering under certain pressure

OLYMPUS GX71 OM ＆ EDS are applied to observe the microstructure and to analyze the composition of Al - 15% Mg alloy obtained through sintering under certain pressure, and the phase transition of Al/Mg powder during sintering were discussed. The results show that interdiffusion between AI and Mg powders happens during sintering. γ（ Al12Mg17 ）phase first forms in the edge of Mg powder, then it transforms into β （Al3Mg2） phase. This transformation will not stop until the Mg particle transform into γ phase, then β phase from outside to inside. If temperature decreases, β phase will precipitate in an extremely small - scale ; Al - 15% Mg alloy with density less than 2.5g/cm^3 have been obtained under the pressure 150MPa for 3 - 4h at 420℃, and the ratio of testing density to theoretical density is more than 98%.