激光快速熔凝Cu-75％Sn过包晶合金中ε相向包晶η相的转变  

TRANSITION FROM PRIMARY ε PHASE TO PERITECTIC η PHASE IN Cu-75%Sn HYPERPERITECTIC ALLOY UNDER LASER RAPID SOLIDIFICATION

作　　者：吕海燕[1] 李双明[1] 钟宏[1] 刘林[1] 傅恒志[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,西安710072

出　　处：《金属学报》2008年第7期843-847,共5页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目50395102;新世纪优秀人才支持计划项目资助~~

摘　　要：采用激光表面快速熔凝设备,研究了Cu-75%Sn过包晶合金在1至100 mm/s扫描速度范围内的凝固组织及其变化规律.当扫描速度增大到20 mm/s时,包晶η相可直接从液相中析出,而无需通过包晶反应(ε+L→η)生成,最终凝固组织由包晶,7相和富Sn相组成.基于最高界面生长温度判据,针对凝固过程中初生ε相和包晶η相皆为金属间化合物的特性,对Umeda等人给出的包晶合金竞争生长模型进行了修正.利用修正的模型计算了初生相从ε相到η相转变的临界凝固速度为19.5 mm/s,与实验获得的10—19.3 mm/s基本吻合.Laser rapid solidification experiments were performed on Cu 75%Sn hyperperitectic alloy to investigate microstructure evolution at scanning velocities ranging from 1 to 100 mm/s. As the scanning velocity is higher than 20 mm/s, peritectic ηphase will directly solidify from the liquid instead of by peritectic reaction （ε＋L-η）, and no primary ε phase forms in the solidified microstructures. By considering that primary ε and peritectic η phases are both intermetallic compounds in Cu-75%Sn alloy, the competitive growth model proposed by Umeda et al for the growth of peritectic alloys is modified based on the maximum growth temperature criterion. Using this modified model, the calculated solidified critical velocity for primary ε phase transition to η phase is 19.5 mm/s, which approaches the experimental results of 10 to 19.3 mm/s.

关 键 词：Cu-75%Sn 包晶合金 激光表面快凝 相转变 

分 类 号：TG132.32[一般工业技术—材料科学与工程]