CAJ | 학술논문

采用热力学计算与实验相结合的方法,研究了两种高强韧 Al- Zn- Mg- Cu 合金铸态及均匀化态的显微组织和相构成.铸态 A 合金主要由 Mg(Zn,Al,Cu)2相和少量 Al2 Cu 相组成,而铸态 B 合金仅含 Mg(Zn,Al,Cu)2相.热力学计算显示,A和 B 两种合金的实际凝固过程介于 Lever Rule 和 Scheil Model 两种模拟结果之间,由于合金成分不同而导致的铸态 A 和 B 合金中各相含量差异与 Scheil Model 模拟所得到的各相摩尔分数变化规律基本一致.经常规工业均匀化处理(460℃保温24 h),铸态 A 和 B 合金中存在的 Mg(Zn,Al,Cu)2或 Al2 Cu 相均能充分回溶,并得到单相α(Al)基体,这与热力学计算所得到的Al-Zn- Mg- Cu 四元系统在7.5% Zn 条件下460℃等温相图相符合.
채용열역학계산여실험상결합적방법,연구료량충고강인 Al- Zn- Mg- Cu 합금주태급균균화태적현미조직화상구성.주태 A 합금주요유 Mg(Zn,Al,Cu)2상화소량 Al2 Cu 상조성,이주태 B 합금부함 Mg(Zn,Al,Cu)2상.열역학계산현시,A화 B 량충합금적실제응고과정개우 Lever Rule 화 Scheil Model 량충모의결과지간,유우합금성분불동이도치적주태 A 화 B 합금중각상함량차이여 Scheil Model 모의소득도적각상마이분수변화규률기본일치.경상규공업균균화처리(460℃보온24 h),주태 A 화 B 합금중존재적 Mg(Zn,Al,Cu)2혹 Al2 Cu 상균능충분회용,병득도단상α(Al)기체,저여열역학계산소득도적Al-Zn- Mg- Cu 사원계통재7.5% Zn 조건하460℃등온상도상부합.
The microstructure and phase components of as-cast and homogenized Al- Zn- Mg- Cu alloys with high strength and toughness were studied by combining thermodynamic calculation with experiments. It is found the secondary phases presented in as-cast alloy A are Mg(Zn,Al,Cu) 2 and a small amount of Al2 Cu; however, only Mg(Zn,Al,Cu) 2 is found in as-cast alloy B. Thermodynam-ic calculation results show that the real solidification paths of alloys A and B fall between simulations by the Lever rule and the Scheil model, and the differences in content of phases in the two as-cast alloys are consistent with the regularity of the calculated mole fraction of phases formed after solidification in the Scheil model. Mg(Zn,Al,Cu) 2 or Al2 Cu phase in as-cast alloys A and B can be dissolved completely after conventional homogenization treatment (holding at 460 ℃ for 24 h), single α(Al) phase can be obtained, and this is consistent with the calculated isothermal section of the Al- Zn- Mg- Cu phase diagram with 7. 5% Zn at 460 ℃ .