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平衡液滴法(equilibrium shape measurement)是一种确定晶体-熔体界面能各向异性参数的有效方法。利用平衡液滴法测量单相固体中夹带的平衡液滴的形状,得到了Al-Si和Al-Si-Sc合金的界面能各向异性参数计算值。通过定向凝固方法制备Al-2%Si和Al-2%Si-0.2%Sc(质量分数,下同)合金杆状试样,使用光学显微镜表征Al-2%Si和Al-2%Si-0.2%Sc合金内部液滴手工连续磨样抛光后多个二维截面形状,计算了二维界面能各向异性参数的大小。利用聚焦离子束(focused ion beam,FIB)技术连续切割了Al-2%Si合金内部液滴,并用Image-J软件重构液滴三维形状,获得了三维界面能各向异性参数值(ε_1=0.0795,ε_2=–0.0056),并且绘制了三维界面能分布和界面刚度的分布图。在此基础上,讨论了平衡温度和Sc元素对界面能各向异性参数的影响。结果表明,对于Al-Si合金,平衡温度为595℃时液滴成分为Al-10.12%Si,金属液中的初生α-Al具有大小为0.0202的界面能各向异性值,而对于Al-Si-Sc合金,平衡温度为595℃时液滴成分为Al-10.08%Si-0.11%Sc(质量分数),金属液中的初生α-Al具有大小为0.0193的界面能各向异性值。
The equilibrium shape measurement is an effective method to determine the anisotropy parameters of the crystal-melt interface. The equilibrium droplet method was used to measure the shape of the equilibrium droplets entrained in the single phase solid. The calculated interfacial energy anisotropy parameters of the Al-Si and Al-Si-Sc alloys were obtained. Al-2% Si and Al-2% Si-0.2% Sc (mass fraction, same below) alloy rod samples were prepared by directional solidification method and characterized by light microscopy using Al-2% Si and Al-2% Si-0.2 % Sc The two-dimensional cross-sectional shape of the droplet inside the droplet was polished by manual grinding and polishing. The anisotropy parameters of the two-dimensional interface were calculated. The internal droplets of Al-2% Si alloy were continuously cut by focused ion beam (FIB) technique and the three-dimensional interfacial anisotropy parameter values were obtained by Image-J software (ε_1 = 0.0795, ε_2 = -0.0056), and plotted the distribution of the three-dimensional interface energy and the distribution of the interface stiffness. On this basis, the effects of equilibrium temperature and Sc element on interfacial energy anisotropy parameters are discussed. The results show that for the Al-Si alloy, the droplet composition is Al-10.12% Si at the equilibrium temperature of 595 ℃ and the interfacial energy anisotropy value of 0.0202 for the primary α-Al in the molten metal. For the Al-Si alloy, -Sc alloy with a droplet composition of Al-10.08% Si-0.11% Sc (mass fraction) at an equilibrium temperature of 595 ° C. The primary α-Al in the liquid metal has an interfacial anisotropy value of 0.0193.