Solidification Microstructure of Laser Additive Manufactured Ti6Al2Zr2Sn3Mo1.5Cr2Nb Titanium Alloy
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- 作者：Qiang Zhang ; Jing Chen ; phd2003cjj@nwpu.edu.cn" class="auth_mail" title="E-mail the corresponding author ; Lilin Wang ; Hua Tan ; Xin Lin ; Weidong Huang
- 关键词：Laser additive manufacture ; Partially melted powders ; Equiaxed grains
- 刊名：Journal of Materials Science & Technology
- 出版年：2016
- 出版时间：April 2016
- 年：2016
- 卷：32
- 期：4
- 页码：381-386
- 全文大小：2555 K
文摘
Solidification microstructure of powder fed laser additive manufactured Ti
class="glyphImg imgLazyJSB">6Alclass="glyphImg imgLazyJSB">2Zrclass="glyphImg imgLazyJSB">2Snclass="glyphImg imgLazyJSB">3Moclass="glyphImg imgLazyJSB">1.5Crclass="glyphImg imgLazyJSB">2Nb titanium alloy was investigated. The results showed that by deliberately increasing the powder feed rate, partially melted powders were retained at the top of the molten pool, which can promote heterogeneous nucleus. Thus, each cladding layer is composed of two regions: (i) randomly orientated cellular structure region caused by partially melted powders at the top of each cladding layer; and (ii) epitaxial cellular structure region adjacent to the fusion line. Usually, randomly orientated cellular structure region was totally remelted for a wide range of process conditions. The remelting effect ensures the continuity of epitaxial growth of cellular structure and leads to the formation of columnar β grains. In order to obtain equiaxed grains the scanning velocity and powder feed rate should be carefully selected to enlarge the randomly orientated cellular structure region.
class="glyphImg imgLazyJSB">6Alclass="glyphImg imgLazyJSB">2Zrclass="glyphImg imgLazyJSB">2Snclass="glyphImg imgLazyJSB">3Moclass="glyphImg imgLazyJSB">1.5Crclass="glyphImg imgLazyJSB">2Nb titanium alloy was investigated. The results showed that by deliberately increasing the powder feed rate, partially melted powders were retained at the top of the molten pool, which can promote heterogeneous nucleus. Thus, each cladding layer is composed of two regions: (i) randomly orientated cellular structure region caused by partially melted powders at the top of each cladding layer; and (ii) epitaxial cellular structure region adjacent to the fusion line. Usually, randomly orientated cellular structure region was totally remelted for a wide range of process conditions. The remelting effect ensures the continuity of epitaxial growth of cellular structure and leads to the formation of columnar β grains. In order to obtain equiaxed grains the scanning velocity and powder feed rate should be carefully selected to enlarge the randomly orientated cellular structure region.