过共晶Cu-Cr合金定向凝固特性研究  

Study on the Directional Solidification of Hypereutectic Cu-Cr Alloy

作　　者：毕晓勤[1] 傅恒志[2] 

机构地区：[1]河南工业大学材料科学与工程学院,河南郑州450007 [2]西北工业大学凝固技术国家重点实验室,陕西西安710072

出　　处：《铸造技术》2009年第5期637-641,共5页Foundry Technology

基　　金：河南省自然科学基金(0511052400)

摘　　要：考察了Cu-1.7%Cr和Cu-5.6%Cr过共晶合金的定向凝固组织。实验表明:Cu-1.7%Cr和Cu-5.6%Cr过共晶合金定向凝固组织是由初生β相、α相和(α+β)共晶组成;α相是基于竞争生长机制的一种非平衡凝固组织。凝固速度和成分对初生β相生长形态产生显著影响。在Cu-1.7%Cr合金中,初生β相生长为等轴颗粒状,且受凝固速度的影响不大。在Cu-5.6%Cr合金中,随着凝固速度的增加,初生β相的生长形态经历了树枝状到等轴颗粒状的演变;α相包裹树枝状的初生β相生长,形成了类似"包晶"结构的微观形貌特征;颗粒状的、均匀分布的初生β相有利于α相的定向生长。降低合金成分和提高凝固速度有助于获得最佳组织形态的复合材料。Microstructures of the hypereutectic Cu-1.7 % Or alloy and Cu-5.6 % Or alloy during the directional solidification were observed. The results show that the their microstructures consist of primary β phase, a phase and eutectic （α＋ β）. Based on the competitive growth mechanism, the α- phase is the non-equilibrium microstructure. The effect of solidification rates and element on the primary β-phase morphology are notable. The primary β phase in the hypereutectic Cu-1.7% Or alloy grow for the equiaxed particles. With the increase of solidification rates, the primary β phase in the hypereutectic Cu-5. 6% Or alloy undergo the evolution from the dendritic crystal to the equiaxed particles. The a phase develops around the dendritic β phase so that the microstructural morphology is parallel to the peritectic alloy. The uniform distribution of the equiaxed β-phase particles is propitious to the α-phase directional growth. Reducing the composition and improving the solidif.ication rate will help the composite material.

关 键 词：过共晶 CU CR合金 凝固特性 

分 类 号：TG113[金属学及工艺—物理冶金] TG146.11[金属学及工艺—金属学]