Comparison Of Ti-6al-4v Powder And Bulk Specimen Properties Across Manufacturers In Laser Powder-Blown Ded

The investigation and comparison of 4 different Ti64 powder feedstocks from 3 different manufacturers was done to determine if the quality of the powder had a profound effect on the properties of the bulk specimens despite using the same processing parameters. The characteristics of the powder observed are the atomization process used, particle size distribution, flowability, and its density. The Ti64 printing parameters for directed energy deposition that were kept consistent were the feed rate, scanning speed, and laser power. Coupons with varying build angles (0-30°) were printed to measure the impact of overhangs on bulk specimen properties (ultimate tensile strength, hardness, and strain). Additionally, mechanical testing specimens that are to be fabricated from the coupons will be made in different orientations from the printing direction to observe the anisotropic properties that are quite prevalent within additively manufactured products. Coupons were also stress relieved to reduce the residual stress and preserve and analyze as close to the as-built microstructure of the bulk specimens when fabricated. The powder feedstock was observed to have typical defects seen in the atomization process, such as satellites, porosity, irregular shapes, and agglomerates. The powders experience similar densities and mass flow rates, but possess a discrepancy in their volume flow rate. When the powders were processed and tested, a discrepancy in UTS, Strain, and hardness was observed within the powder variants. Statistical analysis was also used to validate this variance mathematically and to determine whether the observed variables were indeed contributors to the variance in mechanical properties.