石油焦制备Al-Ti-C-Ce母合金显微组织及凝固机理研究

The Microstructure and Solidification Mechanism of Al-Ti-C-Ce Prepared by Petroleum Coke

摘要:

采用X射线衍射（XRD）、扫描电子显微镜（SEM）、能谱仪（EDS）研究了Al-Ti-C-Ce母合金显微组织。结果表明：该母合金由α（Al）、（AlTi）、（TiC）、（Ti2Al20Ce）相组成；合金中分布具有复合结构的第二相。线分析表明：合金中C分布均匀，粒子内部Al含量偏低，粒子与基体间界面区域Ce含量最高，粒子内部铈含量略低，第二相粒子内部是元素Ti含量分布最集中的区域。母合金的凝固过程为：合金熔体中Ti、Al、C首先形成高熔点TiC、（TiAl）质点相；以TiC相为一次晶核，（TiAl）相偏聚在TiC相表面，形成TiC-（TiAl）复合晶核，Al通过包晶反应形成微细TiC-（TiAl）-α（Al）一级复合晶核；以某一能量较高、团簇尺寸较大的一级复合晶核为核心，其它一级复合晶核偏聚在其表面，形成二级复合晶核。二级复合晶核形成三级复合晶核，依次类推，形成复合粒子的钛富集区。钛富集区作为超级“晶核”，并作为Ti2Al20Ce和（Al4Ce）形核的“基底”，在其表面形成富铈的壳层，α（Al）通过富铈的壳层成核。

Abstract:

The microstructure of an Al-Ti-C-Ce alloy was studied by XRD,SEM,and EDS. This mother alloy consisted of α(Al),(AlTi),(TiC),and (Ti2Al20Ce) phases,and there was a second phase of a composite structure in the alloy.The TiC phase was the primary crystal nucleus,and the (TiAl) phase was segregated on the surface of TiC phase to form a TiC-(TiAl) composite crystal nucleus. Al formed a fine TiC-(TiAl)-α(Al) primary composite crystal nucleus by a peritectic reaction.The primary composite crystal nucleus with higher energy and larger cluster size was taken as the core,and other composite crystal nuclei were segregated on its surface to form a secondary composite crystal nucleus.Next,the secondary composite crystal nucleus formed the tertiary composite crystal nucleus,and so on,to form the titanium-enriched area of composite particles.