(西安理工大學 材料科學與工程學院，西安 710048)
摘 要: 研究快速凝固Cu-xSn(x=7%, 13.5%, 質(zhì)量分數(shù))合金的相結(jié)構(gòu)、組織形態(tài)和枝晶生長特性，將金屬熔體熱傳導(dǎo)方程與Navier-Stokes方程相耦合，從理論上計算液態(tài)合金的冷卻速率。結(jié)果表明：在急冷快速凝固條件下，Cu-7%Sn合金形成過飽和的單相a-Cu固溶體組織；Cu-13.5%Sn合金形成以亞穩(wěn)的Cu13.7Sn相為主相、a-Cu為第二相的快速凝固組織；隨著冷卻速率的增大，溶質(zhì)截留效應(yīng)增強，合金相結(jié)構(gòu)由復(fù)相向單相轉(zhuǎn)變；沿垂直于輥面方向上合金的組織形態(tài)依次為近輥面細小等軸晶、中部柱狀晶及自由面粗大等軸晶；增大冷卻速率，晶體形態(tài)由柱狀晶向等軸晶轉(zhuǎn)變；在急冷快速凝固過程中，a-Cu和Cu13.7Sn相均以枝晶方式生長；隨溫度梯度的增大，晶體生長速率呈線性增大。
關(guān)鍵字: Cu-Sn合金；單輥法；急冷快速凝固；晶體生長
（School of Materials Science and Engineering, Xi’an University of Technology, Xi’an 710048, China）
Abstract:The phase structure and microstructural characteristics of rapidly solidified Cu-xSn(x=7%, 13.5%, mass fraction) alloys were investigated. The cooling rate was calculated theoretically by coupling the heat conduct equation and Navier-Stokes equation. The results show that under rapid solidification condition, the single phase a-Cu solid solution is formed in Cu-7%Sn alloy. The microstructure of Cu-13.5%Sn alloy consists of main phase Cu13.7Sn and a few of a-Cu phase. With increasing cooling rate, the effect of solute trapping is enhanced, and the phase structure changes from multiphase to single-phase. The microstructures of the alloy along the direction vertical to wheel surface are characterized by fine equiaxed, columnar and coarse equiaxed grain, respectively. Both a-Cu and Cu13.7Sn phase grow in the manner of dendritic growth. With increasing temperature gradient, the growth rate of columnar crystals increases linearly.
Key words: Cu-Sn alloy; melt-spun method; rapid solidification; crystal growth
