Effect of powder oxygen content on the microstructure and properties of Co–Cr dental alloys fabricated by selective laser melting

ABSTRACT

A high oxygen content can lead to metallurgical defects such as holes and microcracks in the products of selective laser melting (SLM) that significantly reduce the density and mechanical properties of a denture. In this study, a batch of a Co–Cr alloy powder was subjected to forced oxidation. SLM was used to prepare specimens from the powder before and after the treatment for the performance tests. The results showed that Co–Cr alloy powders with oxygen contents 184 and 616 ppm could both achieve good shaping of the specimens under identical SLM conditions. There was no significant difference between the specimens in terms of fuselage morphology, microstructure, density, tensile strength, yield strength and hardness. However, the elongation of the alloy synthesised using the higher oxygen content powder was significantly lowered, but still higher than that required by the ASTM F75 Casting Standard of the United States.

KEYWORDS:

• Selective laser melting
• Co–Cr alloy powder
• oxygen content
• relative density
• mechanical properties
• elongation

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes on contributors

Wei Zhang Ph.D, 1. Associate Professor, Powder Metallurgy Research Institute, Central South University, Changsha, People's Republic of China; 2. Head Engineer 3D Printing Division, Henan Huanghe Whirlwind Co., Ltd., Xuchang, People's Republic of China.

Yujia Li, Assistant Engineer, Henan Huanghe Whirlwind Co., Ltd., Xuchang, People's Republic of China.

Songhao Hu, Assistant Engineer, Henan Huanghe Whirlwind Co., Ltd., Xuchang, People's Republic of China.

Mingyang Zhang, Ph.D. candidate, Powder Metallurgy Research Institute, Central South University, Changsha, People's Republic of China.

Songhai Huang, Assistant Engineer, Henan Huanghe Whirlwind Co., Ltd., Xuchang, People's Republic of China.

Tianyun He, General Manager of 3D Printing Division & Vice President, Henan Huanghe Whirlwind Co., Ltd., Xuchang, People's Republic of China.

Yong Liu Ph.D, Professor & Director Powder Metallurgy Research Institute, Central South University, Changsha, People's Republic of China.

Yuchang Wang Ph.D, Head Engineer & Vice President Henan Huanghe Whirlwind Co., Ltd., Xuchang, People's Republic of China.

Additional information

Funding

The authors acknowledge support from the Postdoctoral Foundation Supported Project of CSU (Postdoctoral No. 148700).