摘要
用光学显微镜、扫描电子显微镜、X射线衍射分析、差热分析等手段对低合金化τ型高锌镁合金ZA73的铸态显微组织和凝固特征进行研究。结果表明,金属型铸造ZA73合金的铸态组织由球状等轴-αMg枝晶和在晶界以及枝晶间均匀分布的Mg32(Al,Zn)49化合物组成。结合DSC分析结果和Mg-Zn-Al三元液相面投影图,给出了熔体凝固过程中发生的相变反应和凝固序列。与高合金化τ型高锌镁合金ZA104相比,由于Al、Zn元素含量的降低,ZA73合金具有较高的液相线温度和较宽的凝固温度区间,分别为627℃和283℃,而第二相相变起始温度则低于ZA104合金,约为354℃。
The as-cast microstructure and solidification characteristics of a low-alloying r-type Mg-Zn-Al based magnesium alloy with a nominal element content of 7wt%Zn and 3wt%Al (ZA73) have been experimentally examined using optical microscopy, scanning electron microscopy, X-ray diffraction, and differential scanning calorimetry analysis. The results show that the as-cast microstructure of permanent mould casting ZA73 magnesium alloy consists of a-Mg globular equiaxed dendrite with Mg32 (Al, Zn) 49 compounds as the only secondary phase homogenously distributed in interdendrite. Solidification sequence has been proposed with the help of DSC analysis and Mg-Zn-Al ternary liquidus projection phase diagram. Compared to ZA104 alloy containing larger amounts of alloying element, ZA73 alloy has higher liquidus temperature (-627°C), wider solidification range (-283°C), and lower starting temperature of the second phase transformation (-354°C) due to the decrease of its alloying element contents.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2006年第3期68-70,共3页
Transactions of Materials and Heat Treatment
基金
国家自然科学基金资助项目(50301018)
关键词
镁合金
ZA合金
显微组织
凝固
耐热
Alloying elements
Casting
Differential scanning calorimetry
Heat resistance
Microstructure
Optical microscopy
Phase diagrams
Phase transitions
Scanning electron microscopy
Solidification
X ray diffraction analysis
