Effect of 0.3% Sc on microstructure, phase composition and hardening of Al-Ca-Si eutectic alloys

添加0.3%Sc对Al-Ca-Si共晶合金显微组织、相组成及硬化性能的影响（英文）

The phase composition,microstructure and hardening of aluminum-based experimental alloys containing0.3%Sc,0?14%Si and0?10%Ca(mass fraction)were studied.The experimental study(electron microscopy,thermal analysis and hardnessmeasurements)was combined with Thermo-Calc software simulation for the optimization of the alloy composition.It wasdetermined that the maximum hardening corresponded to the annealing at300?350°С,which was due to the precipitation of Al3Scnanoparticles with their further coarsening.The alloys falling into the phase region(Al)+Al4Ca+Al2Si2Ca have demonstrated asignificant hardening effect.The ternary eutectic(Al)+Al4Ca+Al2Si2Ca had a much finer microstructure as compared to the Al?Sieutectic,which suggests a possibility of reaching higher mechanical properties as compared to commercial alloys of the A356type.Unlike commercial alloys of the A356type,the model alloy does not require quenching,as hardening particles are formed in thecourse of annealing of castings.

研究含0.3%Sc、0-14%Si和0-10%Ca铝基合金的相组成、显微组织和硬化性能。采用实验研究包括扫描电镜、热分析和硬度测试与Thermo-Calc软件模拟相结合的方法对合金的组成进行优化。结果表明,经300~500°C退火处理后合金的硬化效果最好,这是由于Al3Sc纳米颗粒的析出及其进一步粗化。成分在(Al)+Al_4Ca+Al_2Si_2Ca相区的合金呈现明显的硬化效应。三元共晶合金(Al)+Al_4Ca+Al_2Si_2Ca比Al-Si共晶合金的显微组织细得多,这表明实验合金相对于A356系列工业合金具有更高的力学性能。与A356系列合金不同,实验合金不需要淬火处理,因为在其铸件的退火过程中形成了硬化粒子。