Effects of different special casting methods

such as semi-continuous casting

centrifugal casting and vacuum suction

on microstructure and properties of QA110-4-4 aluminum bronze were investigated by OM （optical microscope）

XRD （X-ray diffraction）

tensile testing

SEM （scanning electron microscope） and EDS （energy dispersive spectrometer）. The results show that α phase

γ2 phase and K phase can be observed in the alloys prepared by three kinds of casting methods. In addition

a little metastable β′ phase can be observed in microstructure of vacuum suction alloy. Microstructure of vacuum suction alloy exhibits the finest and the most compactness

in which K phase is homogeneously distributed. Meanwhile

the highest microhardness and tensile strength as well as hardness can be obtained. Inner-outer microstructure of semi-continuous casting and centrifugal casting specimens become heterogeneous

in which K phase is partly agglomerated. Micro-hardness of centrifugal casting specimen exhibits periodically fluctuated from the edge to the heart. The peak hardness is increased nearby the edge.