中文摘要：

采用超音速气雾化法制备了Si质量分数分别为11％、22％、27％、50％的4种Al-Si合金粉末,研究了其粒度分布、表面形貌、微观组织、相组成以及粒度对粉末相含量的影响.结果表明,超音速气雾化Al-Si合金粉末粒度呈双峰分布,平均粒度D5.约为57 μm,粒度分布的几何标准偏差δ不大于1.38;粉末形貌呈球形或近球形,粉末表面有卫星球附着,Si含量的增加将导致粉末表面光洁度变差;粉末颗粒内部存在典型的3种凝固组织：枝晶状Al基体、Al-Si共晶组织以及初生Si组织;初生Si含量随着合金中Si含量的增加而增长,呈现由细颗粒到片状的生长规律;粉末粒度会影响相含量变化,Si质量分数大于11％时,粒径减小将导致共晶相增加.

英文摘要：

Fine droplets of A1-11Si,Al-22Si,Al-27Si and Al-50Si （mass percent） were produced using supersonic high-pressure gas atomization.The particle size of powders was carried out by using an ASTM standard sieve with a vibratory shaker.Scanning electron microscopy （SEM）,optical microscopy （OM） and X-ray diffraction （XRD） were used to the hierarchy of different microstructure.The D50 （particle size on average） of Al-Si alloy powder is 57 μm,and the geometric standard deviation δ is less than or equal to 1.38,which is much lower than conventional gas atomization powder.The morphology of A1-Si powder is spherical or ellipsoidal sphere.There are fine particles adhered to the larger particles.The smooth finish of particles becomes worse with increase of Si content.Dendrite A1,eutectic and primary Si have been observed in the powders.The primary Si content increases and changes fiom particle to slice with the increase of Si content.The powder particle size has an effect on phase content,and the eutectic phase content increases with the decrease of particle size when the Si content is more than 1 1wt％.