电子束成形预合金Ti6Al4V与Ti45Al7Nb混合粉末的组织研究（英文）  

Microstructures of Components Synthesized via Electron Beam Selective Melting Using Blended Pre-Alloyed Powders of Ti6Al4V and Ti45Al7Nb

作　　者：葛文君[1,2] 郭超[1,2] 林峰[1,2] 

机构地区：[1]生物制造与快速成形技术北京市重点实验室,北京100084 [2]清华大学,北京100084

出　　处：《稀有金属材料与工程》2015年第11期2623-2627,共5页Rare Metal Materials and Engineering

基　　金：Beijing Municipal Science and Technology Project(D13110400300000)

摘　　要：研究了电子束快速成形TI6AL4V和Ti45Al7Nb合金混合粉末的特点,得到了成分均匀的Ti22Al3.5Nb2V合金。利用光学显微镜、扫描电镜、电子探针等手段,研究了成形试样的内部组织,并测试了不同组织区域的显微硬度。结果表明:TI6AL4V和Ti45Al7Nb合金混合粉末在电子束成形后,成分均匀,组织具有沉积态特征,包括板条马氏体区和α_2+β两相区,板条马氏体区位于成形零件顶部10个熔覆层厚度,在成形过程中,受再热循环的影响,已凝固形成的马氏体不断分解形成α_2+β两相区,α_2为短棒状,β分布于α_2相之间,在成形件底部,部分α_2相发生等轴化。显微硬度测试结果显示,马氏体区硬度明显高于α_2+β两相区。拉伸结果显示,抗拉伸强度为1214.3MPa,延伸率达到18%。The Ti-based components were synthesized via electron beam selective melting（EBSM） using blended pre-alloyed powders of Ti6A14 V and Ti45A17 Nb with a mass ratio of about 1：1.The microstructures and the chemical compositions of EBSM component samples were investigated by optical microscopy（OM）,scanning electronic microscopy（SEM）,electron probe micro-analyzer（EPMA） and X-ray diffraction（XRD）.The results indicate that an increase of energy density leads to a decrease of fusion defects and an increase of density of the samples.The macro-structure consists of two regions,the martensite phase region and α2＋β phase region.The martensite phase is formed due to the rapid solidification,while the reheating cycles have a remarkable effect on the formation of α2＋β phase.The micro-hardness of martensite region is significantly higher than that of α2＋β phase region.Due to the discontinuous distribution of thick platelet α2 phase along grain boundaries and the high coordinating deformation capability of equiaxial α2 phase,the samples have a tensile strength up to 1214.3 MPa,and a large elongation of 18%.

关 键 词：电子束 快速成形 钛合金 显微组织 

分 类 号：TB383.3[一般工业技术—材料科学与工程]