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为提高Al-Zn-Mg-Cu合金的强度,利用喷射成形的方法制备了含锰Al-Zn-Mg-Cu合金锭,并利用X射线衍射(XRD)、光镜(OP)、扫描电镜(SEM)、透射电镜(TEM)和示差扫描热分析(DSC)研究了其微观组织特征。结果表明:喷射沉积坯主要由晶粒尺寸为5～25μm的细小等轴晶粒、MgZn2和Al6Mn相组成。纳米级的MgZn2颗粒弥散分布于基体,而平均尺寸为5μm的Al6Mn一次相颗粒沿晶界析出。沉积合金中也发现了少量的CuAl2,Al3Zr和共晶组织。沉积坯中缩孔疏松的体积分数约为12%。DSC分析结果说明大部分溶质原子在喷射成形过程中析出,在450℃以下的加热过程中没有明显的热反应发生。随着退火温度的升高,基体晶粒和Al6Mn颗粒单调长大,但Al6Mn颗粒的长大速率显著低于基体晶粒的长大速率。当退火温度高于375℃时,基体晶粒迅速长大。
In order to improve the strength of Al-Zn-Mg-Cu alloy, the manganese-containing Al-Zn-Mg-Cu alloy ingot was prepared by spray forming method and characterized by XRD, OP and SEM SEM), transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The results show that the sprayed blank is mainly composed of fine equiaxed grains with grain size of 5 ~ 25μm and MgZn2 and Al6Mn phases. The nanoscale MgZn2 particles are dispersed in the matrix while the Al6Mn primary particles with an average size of 5μm precipitate along the grain boundaries. Sedimentary alloys also found a small amount of CuAl2, Al3Zr and eutectic. The volume fraction of shrinkage porosity in the blank is about 12%. The results of DSC analysis showed that most of the solute atoms were precipitated during the spray forming process. No obvious thermal reaction occurred during the heating below 450 ° C. With the increase of annealing temperature, the matrix grains and Al6Mn grains grow monotonously, but the growth rate of Al6Mn grains is significantly lower than the growth rate of matrix grains. When the annealing temperature is higher than 375 ℃, the matrix grains grow rapidly.