Additive Manufacturing of High Strength Steels

This thesis explores the strengthening of steels produced by the additive manufacturing process of Laser Powder Bed Fusion for the development of new alloys. Three routes for strengthening steels are investigated - grain refinement, precipitation strengthening using oxides, and precipitation strengthening using intermetallics. This thesis develops an approach to produce ferritic steels with some of the finest grain sizes reported. Alloys within two classes that are difficult to process by traditional methods are also developed to display excellent processability and mechanical properties at either room temperature or elevated temperatures.