工艺参数对电子束选区熔化成形Ti6Al4V合金显微组织的影响

Microstructures of Ti6Al4V Components Synthesized via Electron Beam Selective Melting

摘要:

针对电子束选区熔化的特点，采用不同工艺参数成形了Ti6Al4V实体试样，并利用光学显微镜、扫描电子显微镜、透射电镜和X射线衍射仪研究了气雾化Ti6Al4V粉末在电子束选区熔化成形中的微观组织特征以及不同体能量密度（P/v）对微观组织的影响。结果表明：电子束选区熔化Ti6Al4V合金内部组织为细针状马氏体、魏氏组织和网篮组织，细针马氏体区位于试样成形顶部；随着体能量密度的增加马氏体区高度由7~8个铺粉层厚增加到22~25个铺粉层厚，内部组织由细长片状魏氏组织变为魏氏组织和网篮组织组成的双态组织，片状α相的厚度也由1~2 μm增加到2~4 μm

Abstract:

Pre-alloyed Ti6Al4V powder was used to fabricate solid components by Electron Beam Selective Melting (EBSM). The characteristics of microstructures of the powder were investigated using OM, SEM, TEM and XRD. Results show that the EBSMed Ti6Al4V alloy contains fine-acicular martensite, basket-weave (α+β) as well as widmanstatten (α+β), and the martensite mainly concentrates at the last dozens of forming layers. With the increase of P/V, the height of martensite region rises from 7~8 forming layers to 22~25 forming layers. In addition, the mixed internal microstructure of basket-weave and widmanstatten is formed instead of lamellar widmanstatten microstructure. Meanwhile, the thickness of lamellar α phase increases from 1~2 μm to 2~4 μm