利用定量金相技术研究了亚共晶铝硅合金在磁搅拌连续冷却过程中一次固相的形成及演变规律。结果表明， 一次固相首先在型壁上形核和长大， 并具有粒状、条状和树枝状三种形态。随后，在搅拌作用下从型壁上脱落进入熔体内部， 随熔体做整体运动的同时还会发生自旋运动。运动过程中，粒状晶向球形演变， 条状和树枝状游离晶则会发生颈缩和熔断， 增殖为若干个小的粒状晶， 并最终演变成以近球形粒状非枝晶为主的演变组织 The formation and evolution of the primary solid phase of the hypoeutectic Al-Si alloy during continuous magnetic stirring were studied by means of quantitative metallographic techniques. The results show that the first solid phase firstly nucleates and grows on the wall, and has three forms: granular, strip and dendritic. Afterwards, it falls off from the mold wall and enters into the melt under the action of agitation, and also undergoes spin movement along with the whole movement of the melt. In the process of movement, the granular crystal changes into a spherical shape, and the strips and dendritic free crystals are necked and fused, multiplying into a few small granular crystals and finally evolving into an evolutionary organization mainly of near-spherical granular non-dendrites