The effect of cooling rate on the microstructure of ZA48 alloy was investigated. The alloy was prepared using a relatively simple technique, i e, rapid cooling of the melt in a steel wedge mould. The dependence of mic...The effect of cooling rate on the microstructure of ZA48 alloy was investigated. The alloy was prepared using a relatively simple technique, i e, rapid cooling of the melt in a steel wedge mould. The dependence of microstructure on the cooling rate （about 40 to 10^3 K/s） was determined by the secondary dendrite arm space size measurement, optical microscopy（OM）, and transmission electron microscopy （TEM）. It is found that the matrix structure over a large cooling rate is composed of α-Al dendrite and eutectoid （α＋η）, the size of α-Al dendrite decreases with increasing cooling rate. The relationship between the cooling rate and the secondary dendrite arm space size has been established. TEM shows that a large number of small and dispersed precipitations can be seen in the primary α phase of tip region. Electron diffraction pattern shows that the precipitate phase is Zn3Mg2 phase.展开更多
文摘The effect of cooling rate on the microstructure of ZA48 alloy was investigated. The alloy was prepared using a relatively simple technique, i e, rapid cooling of the melt in a steel wedge mould. The dependence of microstructure on the cooling rate （about 40 to 10^3 K/s） was determined by the secondary dendrite arm space size measurement, optical microscopy（OM）, and transmission electron microscopy （TEM）. It is found that the matrix structure over a large cooling rate is composed of α-Al dendrite and eutectoid （α＋η）, the size of α-Al dendrite decreases with increasing cooling rate. The relationship between the cooling rate and the secondary dendrite arm space size has been established. TEM shows that a large number of small and dispersed precipitations can be seen in the primary α phase of tip region. Electron diffraction pattern shows that the precipitate phase is Zn3Mg2 phase.
