Microstructural characterization of laser surface melted AISI M2 tool steel

Area of Science:

• Materials Science
• Metallurgy
• Surface Engineering

Background:

• High-speed steels like AISI M2 are critical in demanding industrial applications.
• Understanding surface modifications is key to enhancing material performance.
• Laser surface melting offers a novel approach to tailoring steel properties.

Purpose of the Study:

• To investigate the microstructural evolution of AISI M2 high-speed steel after Nd:YAG continuous wave laser surface melting.
• To analyze the effects of varying laser scanning speeds and beam diameters on the surface layer.
• To characterize the resulting microstructures and carbide formations.

Main Methods:

• Laser surface melting using a Nd:YAG continuous wave laser.
• Microstructural analysis via light optical microscopy (LOM) and scanning electron microscopy (SEM).
• Phase identification using X-ray diffraction (XRD).

Main Results:

• Laser surface melting induced significant microstructural changes.
• A distinct melted zone with a dendritic structure was observed.
• A partially melted zone exhibited a heterogeneous cellular structure.
• M(2)C carbides with diverse morphologies were identified in the resolidified layer.

Conclusions:

• Laser surface melting effectively modifies the microstructure of AISI M2 steel.
• The study provides detailed insights into the dendritic and cellular structures formed.
• Characterization of M(2)C carbides aids in understanding wear resistance improvements.
• This method offers an alternative to complex sample preparation for electron microscopy.