Effect of Laser Power on Microstructures and Mechanical Properties of Deposited Ultra-High Strength Steel Processed by Laser Metal Deposition
摘要
This paper aims to investigate the effect of laser power on the microstructure and mechanical properties of ultra-high strength steel fabricated by Laser metal deposition. The influence of laser power on the phase composition, grain size, density, cracking,, and mechanical properties of the sample was studied through x-ray diffraction, scanning electron microscopy, electron backscatter diffraction, tensile testing, and impact testing. The results indicate that the microstructure characteristics of all samples are similar within the laser power range of 1900-2400 W. Most grains grow along the < 110 > direction. In addition, the sample contains a large amount of BCC phase and a relatively small amount of FCC phase. As the laser power increases, the sample average density shows a trend of first decreasing and then slightly increasing between 1900 and 2400 W. The highest density at 2200 W is 99.45%. When the laser power is 2100 W, the maximum tensile strength of the sample is 1827Mpa, the maximum elongation is 15.5%, and the maximum impact toughness is 83.53 J/cm-2. Finally, the relationship between the average grain size, tensile strength, and impact toughness within the XOZ plane was analyzed. The comprehensive mechanical properties of the formed samples obtained in this study can meet higher manufacturing requirements and promote the application of additive manufacturing technology in various fields.