Pages

Monday, 30 September 2013

Laser Treatments Yield Smoother Metal Surfaces

Ever since the Bronze Age, metals have been cast in different shapes for different applications. Smooth surfaces that are resistant to corrosion are crucial for many of the present-day uses of cast metals, ranging from bio-implants to automotive parts. Yingchun Guan, from the A*STAR Singapore Institute of Manufacturing Technology (SIMTech) and her co-workers have shown how different laser-processing methods improve metal surfaces and protect them against corrosion1.
Laser processing involves scanning a high-intensity laser beam multiple times across the surface of a metal. Each scan by the laser beam ‘writes’ a track in the surface, which partially melts the metal. Consecutive tracks can overlap — the degree to which affects how well the melting caused by these tracks will smooth the surface of the metal. The scanning speed can also affect the surface melt.

Optical microscope cross-sections of the alloy surface show that increases in laser beam overlap during processing reduces the number of small cracks (top left, 25% overlap; top right, 50%; bottom left, 75%; and bottom right, 90%). (Credit: Copyright Elsevier 2013)