Effect of Process Parameters on Microstructure of Ti48Al2AlCr2Nb Alloy Made by Single Laser Metal Deposition

Author of the article:LI Xiaolei 1,2 , YUAN Gang 1 , ZHANG Kelun 1 , CUI Lujun 1 , GUO Shirui 1 , CUI Yinghao 1 , XU Chunj

Author's Workplace：1. School of Mechanical and Electronic Engineering, Zhongyuan University of Technology, Zhengzhou 450007, China; 2. School of Material Science and Engineering, Xi'an University of Technology, Xi'an 710048, China

Key Words： laser metal deposition technology; γ-TiAl alloy; surface morphology; microstructure

Abstract：Ti48Al2Cr2Nb alloy samples were prepared by laser metal deposition (LMD) technology. The surface
morphology, geometric characteristics, cracks, microstructure and microhardness of the samples were studied under
different processing conditions. The results show that the laser power has the greatest influence on the morphology of the
sedimentary layer. With the increase of the laser power, the crack of the sedimentary layer decreases and the welding width
increases gradually. The dilution rate also increases with the increase of laser power. When the laser power increases from
2 000 W to 3 000 W, the dilution rate increases from 0.334% to 0.764%. At the same time, with the increase of laser
power, the microstructure changes from columnar crystal to equiaxed crystal, and the microstructure of the sedimentary
layer is mainly composed of α 2 and γ phases. Under the condition of different processing parameters, the texture of the
microstructure also changed. When the laser power increases, the microhardness decreases, and when the laser power
reaches 3 000 W, the hardness value decreases to 386.3 HV.