Microhardness and Microstructure Analysis of the LPBF Additively Manufactured 18Ni300

Area of Science:

• Materials Science
• Metallurgy
• Additive Manufacturing

Background:

• 18Ni300 maraging steel is a high-performance alloy used in demanding applications.
• Laser Powder Bed Fusion (LPBF) is a key additive manufacturing technique for producing complex metal parts.
• Understanding the microstructure-property relationship in LPBF-processed steels is crucial for quality control.

Purpose of the Study:

• To analyze the phase components, microstructure, and hardness of 18Ni300 maraging steel produced via LPBF.
• To establish a correlation between hardness and distinct microstructural features (cellular vs. columnar).
• To identify potential defects and facilitate microstructure examination before surface treatment.

Main Methods:

• X-ray diffraction (XRD) for phase component analysis.
• Scanning Electron Microscopy (SEM) for microstructural examination.
• Systematic microhardness distribution measurements across various locations and structures.

Main Results:

• Significant variations in hardness were observed between cellular and columnar structures, dependent on measurement location relative to cell boundaries.
• Hardness values were notably higher in regions exhibiting a combination of cellular structures and multiple layers.
• Consistent patterns in microhardness distribution were identified across samples.

Conclusions:

• The study successfully correlated microstructural features with hardness in LPBF-processed 18Ni300 maraging steel.
• LPBF process parameters influence the resulting microstructure and mechanical properties.
• The findings provide valuable insights for optimizing LPBF processes and ensuring material quality.