Chinese Journal of Lasers, Volume. 37, Issue 2, 593(2010)
Microstructure and Phase Structure of Laser Solid Forming Ti2AlNb-Based Alloy
Ti2AlNb-based alloys of two different compositions were deposited using a 5 kW CO2 laser. Optical microscope (OM),scanning electron microscope (SEM),energy-dispersive spectrometer (EDS),X-ray diffraction (XRD) and microhardness testing method,were used to investigate the typical microstructure evolution,phase transformation and the corresponding hardness evolution. Experimental results show that for Ti-20%Al-27%Nb (atomic fraction) (A1),the phase transformation occurrs:B2→B2+O→B2 along the laser deposition direction. While Ti-22%Al-27%Nb (A2) is mainly composed of β(TiNb) dendritic and B2+O in the interdendritic. The primary dendrite trunk spacing changes from 25 μm to 80 μm along the deposition direction. For the two different compositions Ti2AlNb-based alloys,the microhardness variation of A1 alloy along the deposition direction is low→high→low,which agrees well with the corresponding microstructure and phase transformation. The microhardness of A2 alloy distributes uniformly except the local region of the dendritic.
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Chen Jing, Jiang Guozheng, Lin Xin, Huang Weidong. Microstructure and Phase Structure of Laser Solid Forming Ti2AlNb-Based Alloy[J]. Chinese Journal of Lasers, 2010, 37(2): 593
Category: laser manufacturing
Received: May. 22, 2009
Accepted: --
Published Online: Feb. 3, 2010
The Author Email: Jing Chen (phd2003cjj@nwpu.edu.cn)