在定向凝固条件下 ,研究了偏晶系Al Bi合金的自生复合行为 ,考察了凝固速度和温度梯度对其自生复合行为的影响。试验结果表明 :偏晶反应可以生成两相有序排列的共生组织。在一定的温度梯度下 ,随着凝固速度的提高 ,组织由规则形态的纤维 (或串状 )组织向弥散分布的不规则组织转变。当G/V >1 6 0× 1 0 9K·s/m2 时 ,能得到规则的组织 ;反之 ,则得到不规则的弥散分布的组织 ,纤维间距与凝固速度的关系满足λ2 V =C。 Under directional solidification conditions, the self-forming behavior of the crystallite Al Bi alloy was investigated. The effect of solidification rate and temperature gradient on the self-compositing behavior was investigated. The experimental results show that the partial crystallographic reaction can produce two-phase orderly arranged symbiotic tissue. Under the certain temperature gradient, with the increase of the solidification rate, the microstructure changes from regular fiber (or string-like) structure to dispersedly distributed irregular structure. When G / V> 160 × 109K · s / m2, the regular structure can be obtained. On the contrary, the irregular distributed structure can be obtained. The relationship between fiber spacing and solidification speed satisfies λ2 V = C.