Agile Alloy Design for Additive Manufacturing Using Computational Thermodynamics: Hot Work Tool Steel and Maraging Steel Case Studies

C-bearing tool steels with optimum combination of strength, toughness, wear, and tempering resistance show limited weldability, and processability by laser-based additive manufacturing (AM) processing, such as laser powder bed fusion (L-PBF). Because of this, highly alloyed Co-containing ultrahigh-strength maraging steels with excellent weldability re-emerged as commercialized alternatives for the use in AM, years after their prime in 1970-90s. However, cobalt in maraging steel becomes an obstacle in driving the shift towards sustainability. Lower thermal conductivity, wear damage, and in some cases, inferior thermal fatigue behavior are among other limitations of maraging steels. We report on the use of cost, and time-efficient computational alloy design in developing customized alloy powders to overcome these obstacles in view of the application-specific requirements. Microstructure, properties, and performance of Co-free Fe-Ni maraging systems, Co-containing Fe-Ni-C martensite with improved wear resistance, and Co free C-bearing hot work tool steel tailored for enhanced processability by L-PBF are presented and discussed.