Hot Deformation Behaviour of Additively Manufactured 18Ni-300 Maraging Steel

Area of Science:

• Materials Science
• Metallurgical Engineering
• Additive Manufacturing

Background:

• Additive manufacturing (AM) enables complex geometries but requires post-processing optimization for high-performance alloys like 18Ni-300 maraging steel.
• Understanding the hot workability of AM maraging steel is crucial for developing efficient forming processes.

Purpose of the Study:

• To investigate the hot compression behavior and microstructural evolution of additively produced 18Ni-300 maraging steel.
• To determine the material constants for a constitutive relationship governing its hot deformation.
• To assess the hot workability and compare it with conventionally fabricated counterparts.

Main Methods:

• Hot compression tests conducted on a Gleeble thermomechanical simulator across temperatures (900-1200 °C) and strain rates (0.001-10 s⁻¹).
• Microstructural analysis using light microscopy and scanning electron microscopy with electron backscatter diffraction (EBSD).
• Constitutive modeling using experimental flow stress data.

Main Results:

• Dynamic recrystallization (DRX) predominates at high temperatures and strain rates; dynamic recovery (DRV) dominates at lower conditions.
• Experimental data used to evaluate material constants for a constitutive relationship.
• The AM 18Ni-300 steel demonstrates good hot workability with activation energy comparable to conventionally fabricated material.

Conclusions:

• The study confirms the excellent hot workability of additively manufactured 18Ni-300 maraging steel.
• Findings support the development of hybrid post-processing technologies for net-shape forging of AM maraging steel parts.
• Optimized forming processes can lead to reduced forces, improved density, and enhanced mechanical properties.