摘要
采用OM、XRD、EDS及宏观硬度测试等手段研究了真空吸铸和离心铸造方式下QAl10-4-4铝青铜的组织演变规律。结果表明,两种铸造方式下组织中相的种类、析出顺序及初始析出温度有较大的不同。真空吸铸条件下,接近铸态的组织由α相、β'相、KⅡ和KⅢ相构成,其相的析出顺序为KⅡ→α→KⅢ;离心铸造条件下,接近铸态的组织中还含有KⅠ和KⅣ相,其相的析出顺序为α+KⅠ→KⅡ→KⅣ→KⅢ,对应的相初始析出温度整体高于真空吸铸,且α相的初始析出温度远高于真空吸铸。KⅠ相的析出与合金中Fe的含量及Fe/Ni值有关,两者越高,越容易析出KⅠ相。两种铸造方式下,随着淬火温度的降低,合金的硬度在整体上均呈现先快速降低后趋于稳定的趋势。但是,真空吸铸样品在淬火温度大于900℃时出现脆化。β→α+KⅢ共析分解对合金的硬度无明显影响。
Microstructure evolution of QA110 -4 -4 aluminum bronze prepared by special casting process, which are known as Vacuum Suction （VS） ＆ Centrifugal Casting （CC）, was investigated via OM（optical microscope）, XRD（X- ray diffraction）, SEM（scanning electron microscope）, Micro- hardness testing etc. The results indicate that the types, precipitation sequence and initial precipitation temperature of phases of the final products are quite different. Quasi cast structure via VS consists of a phase, β＇ phase, KⅡ phase and K. phase, which precipitated in sequence of KⅡ-α-K.. However, KI phase and Krv phase are observed in quasi cast structure via CC, additionally, its precipitation sequence is spotted as α＋KⅠ→KⅡ→KⅣ→KⅢ. Moreover, phase initial precipitation temperatures via CC are relatively higher than that via VS, especially, a phase. Fe content and Fe/Ni ratio connect with the precipitation for K~ phase, consequently, the higher either of the two factors becomes, the easier for K 1 phase to precipitate. With the reducing of the quenching temperature, hardness of alloy prepared by both casting methods show a rapid decline trend followed by a stabilizing state. Furthermore, embrittlements will appear in samples via VS at a quenching temperature higher than 900℃. It is found that the eutectoid decomposed （β→α＋KⅢ ） barely has a significant effect on the hardness of the alloy.
出处
《有色金属加工》
CAS
2013年第1期13-18,共6页
Nonferrous Metals Processing
关键词
QAl10-4-4铝青铜
组织演变
真空吸铸
离心铸造
QAI10 - 4 - 4 aluminum bronze
microstructure evolution
vacuum suction
centrifugal casting
