(中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 413083)
摘 要: 采用溶劑保護(hù)方法制備了合金Mg-9Gd-4Y-0.65Mn和Mg-9Gd-4Y-0.6Zr， 并擠壓成棒材。 通過光學(xué)顯微鏡、 X射線衍射儀、掃描電鏡和透射電鏡等分析研究了這兩種合金鑄態(tài)和變形態(tài)的顯微組織和力學(xué)性能。 結(jié)果表明： 鑄態(tài)含Mn合金的晶粒粗大，而含Zr合金的晶粒細(xì)得多， Zr能有效地細(xì)化Mg-RE合金的晶粒； 熱變形加工使兩種合金的晶粒度大大減小， 拉伸強(qiáng)度大幅提高， 在同等加工條件下， 含Mn合金形變細(xì)化晶粒作用更顯著； 兩種變形合金都有非常高的室溫和300 ℃高溫強(qiáng)度， 但含Mn合金的延伸率較高；含Zr變形鎂合金適宜通過T5處理， 而含Mn變形鎂合金適宜通過T6處理提高其綜合拉伸力學(xué)性能。
關(guān)鍵字: 稀土鎂合金； 顯微組織； 晶粒細(xì)化； 力學(xué)性能
Mg-Gd-Y-(Mn, Zr) magnesium alloys
XIAO Yang， JIANG Hao， DENG Zhen-zhen
（School of Materials Science and Engineering,
Central South University， Changsha 410083， China）
Abstract: Mg-9Gd-4Y-0.65Mn and Mg-9Gd-4Y-0.6Zr alloys were prepared by the fluxing procedures method and then extruded into rods. The microstructures and tensile properties of the alloys both at as-cast state and at deformation state were investigated by using optical microscopy, X-ray diffractometry, scanning electron microscopy, and transmitting electron microscopy. The results show that the grains of the alloy containing Mn at as-cast state are coarser and those of the alloy containing Zr are much finer, which obviously demonstrates grain refining effect of additional element Zr on Mg-RE alloys. Hot extrusion of the two alloys can enormously decrease the grain size and increase their strength. The grain refining effect of the magnesium alloy containing Mn through extrusion will be more remarkable than that of alloy containing Zr. The two extruded magnesium alloys at room temperature and at 300 ℃ have rather high strength， furthermore, the elongation of the alloy containing Mn is higher. It is suggested that the extruded magnesium alloy containing Zr is introduced to precipitation heat treatment to T5 temper for high mechanical properties， while the extruded magnesium alloy containing Mn to T6 temper.
Key words: rare earth magnesium alloys；microstructure；grain refining； mechanical properties
