Effect of process parameters on formability and surface quality of selective laser melted Al-Zn-Sc-Zr alloy from single track to block specimen

摘要

The effects of the laser power and the scanning speed on molten pool shape, liquid metal spreading characteristics, and surface quality of the Al-Zn-Sc-Zr alloy fabricated by selective laser melting (SLM) were studied. The results showed that at the highest laser power of 360 W and the lowest scanning speed of 400 mm/s, the width and penetration of single track reached the maximum values of 244 mu m and 241 mu m. The powders were fully melted, and the liquid metal had more time to spread out when the line energy input is 800 J/m. The hole and balling defects disappeared, and the surface quality of the block specimen was significantly improved. With a decrease in the line energy density, the width, penetration, and overlap ratio of the single track gradually decreased. The surface morphology became rough with less melting and spreading time of the liquid metals. When the line energy density decreased from 800 J/m to 160 J/m, the roughness of the top surface increased from 9.4 to 16.1, and the densities of the block specimen increased from 98.1% to 99.5%.