(1. 蘭州理工大學(xué) 省部共建有色金屬先進(jìn)加工與再利用國(guó)家重點(diǎn)實(shí)驗(yàn)室，蘭州 730050；
2. 蘭州理工大學(xué) 有色金屬合金及加工教育部重點(diǎn)實(shí)驗(yàn)室，蘭州 730050)
摘 要: 采用受控?cái)U(kuò)散凝固(CDS)技術(shù)和冷卻導(dǎo)流器(CC)制備Al-20%Si(質(zhì)量分?jǐn)?shù))合金，研究導(dǎo)流器角度及澆注溫度對(duì)CDS制備Al-20%Si合金初生硅相的影響。結(jié)果表明：CDS和導(dǎo)流器均能細(xì)化初生硅相，且與常規(guī)的CDS過(guò)程相比，引入導(dǎo)流器可以更好地細(xì)化初生硅相，且隨著導(dǎo)流器角度的減小，細(xì)化效果變好。采用820 ℃的Al-30%Si與660 ℃的純鋁混合，導(dǎo)流器角度為30°，澆注溫度為630℃時(shí)，可以得到平均尺寸僅為18.8 μm的初生硅相，且其分布均勻。分析認(rèn)為：CDS可以減小初生硅相生長(zhǎng)前沿的成分過(guò)冷，而導(dǎo)流器可以進(jìn)一步促進(jìn)液體的強(qiáng)迫對(duì)流，使熔體中溫度場(chǎng)和濃度場(chǎng)更均勻，從而改善初生硅的尺寸、形貌及其分布。
關(guān)鍵字: 過(guò)共晶鋁硅合金；受控?cái)U(kuò)散凝固(CDS)；導(dǎo)流器；初生硅相
（1.State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals,
Lanzhou University of Technology, Lanzhou 730050, China;
2. Key Laboratory of Nonferrous Metal Alloys and Processing, Ministry of Education,
Lanzhou University of Technology, Lanzhou 730050, China）
Abstract:Controlled diffusion solidification (CDS) and cooling channel(CC) were used to prepare hypereutectic Al-20%Si (mass fraction) alloy. The effects of cooling channel angles and the pouring temperatures during CDS process on the microstructure including the size, morphology and distribution of primary silicon were studied. The results show that the application of cooling channel after CDS can obviously refine the size of primary silicon, and the better microstructure can be obtained with the decrease of the angle. Especially, the microstructure of liquid pure Al at 660 ℃ mixing with liquid Al-30%Si alloy at 820℃ is the best when the angle of cooling channel is 30° and the pouring temperature is 630 ℃. The primary Si phase with average particle size of only 18.8 μm distribute uniformly in matrix. Analysis results suggest that CDS can reduce the constitutional supercooling in the liquid ahead of the primary Si phase and the application of the cooling channel can cause the forced convection of liquid, temperature field and concentration field in the melt more evenly, thus can improve the particle size, morphology and distribution of primary Si phase.
Key words: hypereutectic Al-Si alloy; cooling channel; controlled diffusion solidification; primary Si phase
