摘要
利用单辊旋转甩带法制备快速凝固过共晶Al-21Si-0.8Mg-1.5Cu合金条带,并对其进行时效处理,采用扫描电镜、透射电镜及XRD技术对快速凝固组织特征进行了表征,研究了时效温度对合金组织及硬度的影响。结果表明:在快速凝固条件下,试验合金中初生硅相的形核和析出受到抑制,α相领先析出,合金元素Cu、Mg全部固溶在过饱和α-Al固溶体中;大量的Si过饱和固溶于α中,其余部分以羽毛针列状共晶形式析出,形成微纳米级亚稳的亚共晶结构。时效处理时,随着时效温度的升高,硅元素从基体中脱溶析出并逐渐聚集长大,形成微小颗粒弥散基体之上;试验合金的显微硬度也发生了变化,出现时效硬化现象。
A rapidly solidified hypereutectic A1-21Si-0. 8Mg-1.5Cu alloys strip was prepared by single roller melt-spinning method. The resultant strip was aged at different temperatures for 4 h. Microstructure of the rapidly solidified alloy was characterized by means of scanning electron microscopy （SEM） , transmission electric microscopy （TEM） and XRD. The effects of aging temperature on the microstructure and microhardness of the experimental alloy were investigated. The results show that the nucleation and growth of primary silicon are suppressed, meanwhile, α-A1 phase is nucleated, which is prior to eutectic under rapidly solidification. All alloying elements Cu and Mg are supersaturated in α-A1 solid solution. Most of Si is supersaturated in α-A1, the rest precipitated by feather-needles-like eutectic silicon micro-nanocrystals. The metastable hypoeutectic structure is formed. During aging process, silicon element is precipitated from the matrix and gradually aggregated up to form small particles distributed in the matrix as the increase of aging temperature. The hardness of experimental alloy is changed, and age-harden phenomenon occurs.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2013年第1期86-89,共4页
Transactions of Materials and Heat Treatment
基金
河南省国际科技合作项目(084300510006)
河南科技大学博士科研基金(2008bs025)
关键词
快速凝固
过共晶铝硅合金
微观组织
时效析出
显微硬度
rapid solidification
hypereutectic A1-Si alloy
microstructure
aging precipitation
microhardness
