Effect of laser power on the microstructure and properties of additive manufactured 17-4 PH stainless steel in different fabrication atmosphere

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2022-04, Vol.839, p.142846, Article 142846
• Main Authors: Wang, De, Cheng, Donghai, Zhou, Zhangyu, Wang, Wenqin, Hu, Bo, Xie, Yujiang, Xiong, Zhenyu, Hu, Dean
• Format: Article
• Language: English
• Subjects: 17-4 PH stainless Steel; Directed energy deposition; Fabrication atmosphere; Heat treating; Heat treatment; Lasers; Martensitic stainless steels; Mechanical properties; Microhardness; Microstructure; Porosity; Precipitates; Precipitation hardening steels; Silicon dioxide; Stainless steel; Thermal accumulation
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2022.142846

The effect of laser power (400, 600, 800 W) on the microstructure and properties, such as porosity, strength and microhardness, of directed energy deposition 17-4 PH stainless steel in different fabrication atmosphere (atmosphere air and atmosphere Ar) was investigated via the view of thermal process. With the increase of laser power, the porosity of the samples decreased, and the Ar atmosphere further enhanced the effect through a power exponent law. The submicron (∼0.5 μm) amorphous SiO2 particles and the nanoscale (∼35 nm) Cu-rich precipitates dispersed in the matrix strengthened the samples, and the dimensions changed when different atmosphere and heat treatment were employed which in turn influenced the strength and microhardness. The mechanical properties were also affected by content of austenite and the release of oxygen, which were dominated by thermal process and heat treatment.