Al-Si和Al-Si-Sc合金晶体-熔体界面能的各向异性  

Anisotropy of Crystal-Melt Interfacial Energy for Al-Si and Al-Si-Sc Alloys

作　　者：王涛[1] 陈晓华[2] 王自东[1] 

机构地区：[1]北京科技大学,北京100083 [2]新金属材料国家重点实验室,北京100083

出　　处：《稀有金属材料与工程》2017年第6期1566-1571,共6页Rare Metal Materials and Engineering

摘　　要：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（ES） is proved to be an effective method to determine the anisotropy of crystal-melt interfacial energy.ES method was used to measure the shape of liquid droplets entrained in single-phase solid,and to calculate anisotropy parameters for Al-Si and Al-Si-Sc alloys.Rod-shaped Al-2wt%Si and Al-2wt%Si-0.2wt%Sc alloy specimens were prepared using the directional solidification process,followed by heat treatment and quenching.Specimens were sectioned normal to the 100 direction.Optical microscopy was used to characterize 2-D droplet shapes obtained by sequential grinding for Al-2wt%Si and Al-2wt%Si-0.2wt%Sc alloys,and then anisotropy parameters of interfacial energy were calculated.3-D morphologies of droplets sliced by focused ion beam（FIB） for Al-2wt%Si alloy were reconstructed with Image-J software.Anisotropy parameters of interfacial energy were calculated（ε1=0.0795,ε2=–0.0056）,and the 3-D interfacial energy and interfacial stiffness were plotted by Matlab software.Based on the experiment results,effects of equilibrium temperature and Sc element on anisotropy parameters of interfacial energy were discussed for Al-Si alloys.The results show that for Al-Si alloy the chemical composition of equilibrium droplet is Al-10.12wt%Si when the equilibrium temperature is 595 °C,and the magnitude of interfacial energy anisotropy is 0.0202 for the primary α-Al in liquid metal.For Al-Si-Sc alloy,the chemical composition of equilibrium droplet is Al-10.08wt%Si-0.11wt%Sc when the equilibrium temperature is 595 °C,and the magnitude of interfacial energy anisotropy is 0.0193 for the primary α-Al in liquid metal.

关 键 词：AL-SI合金 Al-Si-Sc合金 界面能各向异性 聚焦离子束(FIB)切割技术 

分 类 号：TG146.21[一般工业技术—材料科学与工程]