Work

Phase stability in additively manufactured N-doped CoCrMo alloys via in-situ synchrotron X-ray diffraction during tensile testing

Year: 2025

Type: article

Abstract: Nitrogen is a critical yet challenging alloying element to incorporate into metals and alloys due to its inherently low solubility and poor capture efficiency. In this research, we demonstrate that CoCrMo (CCM) alloys manufactured via laser powder bed fusion (LPBF) using N2 gas-atomized precursor powders achieved a remarkably high supersaturated nitrogen content (∼0.19 wt.%). Compared with alloys produced using Ar gas-atomized powders (LPBF CCM-Ar), the as-built LPBF CCM-N alloy exhibits a reduced density of stacking faults (SFs), attributed to the increased SF energy resulting from nitrogen incorporation. Meanwhile, both alloys demonstrate high yield strengths (YS >900 MPa) due to the presence of dense sub-micro Mo/Cr-decorated dislocation cells and SFs. Notably, nitrogen incorporation further enhances the YS (by >60 MPa) and elastic modulus in LPBF CCM-N alloys. In contrast, the LPBF CCM-Ar alloys demonstrated an elevated deformation-induced martensite proliferation rate during tensile deformation, contributing to greater work hardening capacity.

Source: Materials Research Letters

DOI: 10.1080/21663831.2025.2560529

Authors: Decheng Kong, Gaoming Zhu, Daixiu Wei, Guoliang Zhu, Chaofang Dong

Institutions: Shanghai Jiao Tong University, University of Science and Technology Beijing, Helmholtz-Zentrum Hereon, Nanjing University of Science and Technology

Language: English

Topic: Additive Manufacturing Materials and Processes

Subfield: Mechanical Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $1,459

Funder: National Natural Science Foundation of China