摘要
采用热力学计算和实验技术研究铝角的Al-Ca-Fe体系相图,包括液相面投影图和凝固反应。结果表明,与铝固溶体(Al)平衡的不是Al_(3)Fe相,而是一种组成符合化学式Al_(10)CaFe_(2)的三元化合物。通过包晶转变L+Al_(3)Fe→(Al)+Al_(10)CaFe_(2)(638℃,3.3%Ca和0.5%Fe,摩尔分数)发生从二元化合物到三元化合物的转变。与针状Al_(3)Fe相夹杂物不同,三元化合物的初晶和共晶具有致密的形貌。使用第一性原理计算和X射线衍射分析确定三元化合物Al_(10)CaFe_(2)的晶格结构。此外,近共晶合金Al-6%Ca-1%Fe(质量分数)在500~600℃退火后具有细晶组织,过量相的总体积分数约为25%。因此,Al-Ca-Fe体系可用于制造新的铝基复合合金。
The phase diagram of the Al−Ca−Fe system in the aluminum corner,including the liquidus projection and solidification reactions,was studied by using thermodynamic calculations and experimental techniques.The results show that instead of the Al_(3)Fe phase,a ternary compound whose composition corresponds to the formula Al_(10)CaFe_(2)should be in equilibrium with the aluminum solid solution(Al).Thеtransition from the binary to the ternary compound occurs via the peritectic transformation L+Al_(3)Fe→(Al)+Al_(10)CaFe_(2)(at 638℃,3.3 at.%Ca and 0.5 at.%Fe).Primary and eutectic crystals of the ternary compound have a compact morphology,in contrast to needle-shaped inclusions of the Al_(3)Fe phase.First principles calculations and X-ray diffraction analysis were used to determine the crystal lattice structure of Al_(10)CaFe_(2)ternary compound.In addition,the near eutectic alloy Al−6wt.%Ca−1wt.%Fe after annealing at 500−600℃has a fine structure with a total fraction of excess phases of about 25 vol.%.Thus,the Al−Ca−Fe system can be used to create new aluminum-matrix composite alloys.
基金
financially supported by the Russian Science Foundation(No.20-19-00746)(SEM,DSC,thermodynamic calculations)
the federal academic leadership program Priority 2030 of NUST MISIS(DFT,XRD)。
关键词
Al-Ca合金
金属间化合物
相图
相变
显微组织
铝基复合材料
Al−Ca alloys
intermetallic
phase diagram
phase transition
microstructure
aluminum-matrix composites
