On the Mechanical Performance of an L-PBF 316l Part Using the Performance-Line Instrumented Indentation Test...

Area of Science:

• Materials Science
• Mechanical Engineering
• Additive Manufacturing

Background:

• Laser Powder-Bed Fusion (L-PBF) enables complex component fabrication but struggles with mechanical property customization.
• High residual stresses in L-PBF parts challenge standard mechanical testing and design principles.
• Apparent mechanical properties are dependent on location and residual stress, limiting current engineering applications.

Purpose of the Study:

• To present a comprehensive methodology for determining L-PBF 316L mechanical performance.
• To characterize mechanical properties along specific directions (performance lines) and regions (performance zones).
• To introduce a new property to help discriminate residual stress levels.

Main Methods:

• Developed and applied a comprehensive methodology using nanoindentation tests (PL-nIIT).
• Evaluated mechanical performance along five pre-specified directions (PLs) and in six key regions (PZs).
• Utilized indentation modulus, hardness, and a new indentation size effect-free property: loading stiffness rate (LSR).

Main Results:

• PL-nIIT successfully mapped indentation property gradients across the L-PBF 316L deposit.
• PZs demonstrated orientation-dependent mechanical performance, suitable for benchmarking and design.
• Decreasing relative LSR, H_IT, and E_IT values indicated mild compressive residual stress along the build direction.

Conclusions:

• The developed PL-nIIT methodology effectively overcomes limitations in characterizing L-PBF component mechanical performance.
• The inclusion of LSR provides a valuable metric for assessing residual stress distribution.
• This approach facilitates customized mechanical design and performance optimization for L-PBF 316L parts.