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Updated: Jan 25, 2026
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Quantitative Analysis of Vacuum Induction Melting by Laser-induced Breakdown Spectroscopy
Published on: June 10, 2019
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Morphological Development of Sub-Grain Cellular/Bands Microstructures in Selective Laser Melting.
Xihe Liu1, Xin Zhou2,3, Ben Xu4
1School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China. liuxihe.pku@gmail.com.
Materials (Basel, Switzerland)
|April 25, 2019
Summary
Selective Laser Melting (SLM) of 316 L stainless steel reveals complex cellular and band solidification structures. These morphologies arise from convection and instabilities within the mushy zone during the SLM process.
Area of Science:
- Materials Science
- Additive Manufacturing
- Solidification Science
Background:
- Selective Laser Melting (SLM) is an additive manufacturing technique used for metals.
- Understanding solidification microstructures is crucial for material properties.
- 316 L stainless steel is a widely used alloy in various industries.
Purpose of the Study:
- To investigate the solidification morphologies in single-layer and bulk 316 L SLM parts.
- To elucidate the formation mechanisms of observed microstructures.
- To propose a unifying explanation applicable to other FCC alloys processed by SLM.
Main Methods:
- Conducting single-layer and bulk 316 L experiments using Selective Laser Melting.
- Analyzing the solidified top surfaces and internal bulk structures.
- Observing sub-grain patterns and solidification morphologies using microscopy.
Main Results:
- Identified fine submicron-scale cellular (hexagonal, pentagonal, square), elongated cellular, and band solidification morphologies on the top surface.
- Observed coexisting quasi-hexagonal cellular, elongated cellular, and band sub-grain patterns within single macro-solidified grains.
- Demonstrated transitions between quasi-hexagonal cells and elongated cells/bands within the bulk material.
Conclusions:
- Solidification morphologies are attributed to local convection and Bénard instabilities in the mushy zone, driven by temperature and surface tension gradients.
- Quasi-hexagonal cellular convective fields interact with macro-grain solidification to form sub-grain patterns and micro-segregations.
- The proposed mechanism is potentially applicable to other face-center cubic (FCC) alloys processed via SLM, such as Al-Si and Co-Cr-Mo systems.
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