Effect of scanning speed on microstructure and texture of laser surface remelted 1050 Al alloy

Abstract

A typical commercial Al alloy (1050) sheet was subjected to laser surface remelting (LSR) treatment at 400 W and different scanning speeds (2 and 8 mm/s), with dedicated microstructural and textural characterization made for original and LSRed specimens by using multiple characterization techniques. Results show that the as-received material has a typically recrystallized structure consisting of near-equiaxed grains (average grain size (20.4±15.4) μm) and many submicron second phase particles (SPPs). After the LSR treatment, remelting layers of the 2 mm/s and 8 mm/s specimens are mainly composed of columnar grains (with dense fine SPPs inside them), which are coarser than the near-equiaxed grains in the substrate. As the laser scanning speed increases from 2 to 8 mm/s, the depth of the remelted layer is evidently reduced, with the average width of the columnar grains decreasing from (38.0±4.3) to (33.9±2.0) μm. Meanwhile, the SPPs inside grains are significantly refined with largely increased number density. The LSR does not change the main textural characteristic ({100}〈001〉 cube component) of the as-received sheet but leads to the significantly increased textural intensity.