Al-20%Si合金初生硅宏观偏聚和细化的试验研究  

Experimental Study on Macro-Segregation and Refinement of Primary Si in Al-20%Si Alloy

作　　者：贾海龙[1] 张海涛[1] 左克生[1] 何立子[1] 崔建忠[1] 

机构地区：[1]东北大学材料电磁过程教育部重点实验室,辽宁沈阳110819

出　　处：《铸造》2013年第9期865-869,873,共6页Foundry

基　　金：国家自然科学基金资助项目(51204046);教育部项目基本科研业务费项目国家项目培育种子基金(N110408007)

摘　　要：利用铜楔形模铸造,通过凝固过程测温,研究了浇注温度、变质剂对Al-20%Si合金初生硅宏观偏聚的影响,及冷却速率对P、Cr和P-Cr复合变质Al-20%Si合金凝固过程中初生硅形貌和大小的影响规律。结果表明:850℃浇注得到的试样初生硅的宏观偏聚最少,就变质剂对初生硅宏观偏聚效果,Cr变质的明显改善,P-Cr复合变质与Cr变质效果相差不多,但远优于P变质;变质剂对初生硅细化和球化作用,P变质效果最好,P-Cr复合变质次之,都大幅好于Cr变质的效果;初生硅细化效果随冷却速率增加而增强,但当冷却速率在某区间时,初生硅大小随冷却速率的变化不敏感。获得宏观偏聚少,形貌好,尺寸小于20μm的初生硅的最佳工艺条件为:采用P-Cr复合变质,850℃浇注,冷却速率大于10℃/s。The effects of modifiers and pouring temperature on macro-segregation and modification of primary Si in Al-20％Si alloy under different cooling rate was investigated with wedge-shaped mould,meanwhile the effects of P and combined addition of P and Cr on Al-20％Si were also studied in this paper.The results show that the optimal pouring temperature is 850 ℃.Segregation of primary Si could be inhibited with the addition of modifiers.Segregation of primary Si with the addition of Cr improved significantly,so is that of combined addition of P and Cr,and they all better than that with the addition of P.The primary Si particles were well modified by Cr,P or combined addition of P and Cr,but P has a better modification effect than Cr.Combined addition of P and Cr improves the P modification effect and substantially inhabits the segregation of primary Si.The effect of refinement of primary silicon is enhanced with the increasing rate of cooling.When the cooling rate is in a certain interval,the size of the primary silicon of modified Al-Si alloy is not sensitive to changes of cooling rate.Therefore,the best process condition access to less macro-segregation,good morphology,size of primary silicon less than 20 μm is using P-Cr,pouring at 850 ℃ and with the cooling rate beyond 10 ℃/s.

关 键 词：Al-20％Si合金 初生硅 宏观偏聚 细化 

分 类 号：TG244[金属学及工艺—铸造]