Structured porous 17-PH stainless steel layer fabrication through laser powder bed fusion

ABSTRACT

This study aimed to fabricate thin, porous layers of 17-4 PH stainless steel with a defined porosity using laser powder bed fusion (LPBF). The central composite design (CCD) approach was utilized to examine the effect of process parameters on porosity. Three different methods were employed to measure the porosity of 17-4 PH stainless steel samples, i.e. theoretical analysis, buoyancy, and X-ray computed tomography (X-CT). A statistical quadratic regression model is generated that correlates with LPBF parameters to forecast porosity with high prediction accuracy. The maximum obtained porosity is 51.25% ± 0.33% with a laser power of 60 W, a scanning speed of 1800 mm/s, and a hatch spacing of 0.115 mm, which resulted in an average pore size of 24.8 ± 0.38 µm. Permeability was also analysed, as the volume energy density decrease ranges from 19.30 to 14.22 J/mm³, the permeability coefficient increases from 1.39 to 9.41 × 10⁻¹¹ m². In addition, it is observed that the minimum energy density to fabricate the 17-4 PH SS with the highest porosity and free of defects and fragmentation is 14.2 J/mm³.

KEYWORDS:

• Porous layer
• LPBF
• permeability
• porosity

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data that support the findings of this study are available from the corresponding author [A.J.Q], upon reasonable request.

Additional information

Funding

Funding provided by the Future Energy Systems (FES) grant number FES-T06-Q05 is highly appreciated.

Notes on contributors

S. Sardarian

S. Sardarian is a graduate student in the Mechanical Engineering department at the University of Alberta, Canada, pursuing an MSc. Specializing in additive manufacturing. She completed her Meng (2014) in Biomedical Engineering from the University of Birmingham, United Kingdom. Her research interests focus on the fabrication and characterization of additive manufacturing products, and optimizing additive manufacturing processes.

S. Dehgahi

S. Dehgahi is a PhD in Mechanical Engineering with extensive experience in metal additive manufacturing, material science and corrosion engineering. Her current research interest includes laser powder bed, wire arc and fused deposition modeling techniques. Currently, she is a postdoctoral researcher at university of Alberta.

F. Wei

F. Wei is a PhD in Mechanical Engineering with extensive experience in experimental analysis of mass transport in low platinum loading polymer electrolyte membrane fuel cells, with special attention to water transport. His research interests include fuel cells and water electrolysis.

M. Secanell

M. Secanell is a Professor in the Department of Mechanical Engineering at the University of Alberta, Canada, and the director of the Energy Systems Design Laboratory. He received his Ph.D. (2008) and M.Sc. (2004) in Mechanical Engineering from the University of Victoria and a B.Eng. degree (2002) from the Universitat Politècnica de Catalunya (BarcelonaTech). His research interests are in the areas of: a) analysis and computational design of electrochemical energy technologies, such as polymer electrolyte fuel cells, polymer electrolyzers and flywheels, b) fabrication and characterization of polymer electrolyte fuel cells and electrolyzers, c) finite element analysis, and d) multidisciplinary design optimization.

A.J. Qureshi

A.J. Qureshi is an associate professor at the University of Alberta and leads the Additive Design and Manufacturing Systems (ADaMS) Laboratory in the Mechanical Engineering Department. His work includes developing advanced AM systems and materials, such as plasma-transferred arc systems for metal-ceramic parts, robotic wire arc additive manufacturing, and 4D ferromagnetic polymer-metal composites for printing magnets. He also focuses on the quality control of 3D printed parts with in-situ non-contact metrology. His contributions extend to digital design, robotic additive manufacturing, engineering design processes, and manufacturing systems engineering and industry 4.0.