Ultrasonic vibration-assisted laser atomization of stainless steel

• Published in: Powder technology Vol. 321; pp. 89 - 93
• Main Authors: Alavi, S. Habib, Harimkar, Sandip P.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.11.2017; Elsevier BV
• Subjects: Atomization; Atomizing; Capillary waves; Carbon dioxide; Carbon dioxide lasers; Continuous wave lasers; Dendritic structure; Expulsion; Irradiation; Melt expulsion; Melting; Microstructure; Nuclear electric power generation; Particle size distribution; Porosity; Powder; Power consumption; Shrinkage; Size distribution; Stainless steel; Stainless steels; Substrates; Ultrasonic vibration; Ultrasonic vibrations; Vibration; Melt expulsion; Atomization; Ultrasonic vibrations; Stainless steel
• ISSN: 0032-5910; 1873-328X
• DOI: 10.1016/j.powtec.2017.08.007

In this paper, a novel ultrasonic vibration-assisted laser atomization process for producing fine metallic powder with average particle diameter of about 75–95μm is proposed. The process involves irradiation of a high power continuous wave laser on a consumable metallic substrate vibrating at an ultrasonic frequency. The laser irradiation on the vibrating substrate causes surface melting and expulsion of fine droplets. Preliminary results are presented for the atomization of AISI 316 stainless steel using CO2 laser power of 950W and vibration frequency of 20kHz. The average particle size and size distribution is not significantly influenced by vibration displacement consistent with capillary wave theory of atomization. The microstructure of the larger atomized particles showed fine dendritic structure at the surface and shrinkage porosity at the center of particles indicating multiple surface nucleation for solidification. [Display omitted] •A novel ultrasonic vibration-assisted laser atomization is proposed.•Atomization of metallic powder directly from desired consumable substrate.•Capillary wave hypothesis supports the observed particle size.•Particle size is not affected by variation in ultrasonic vibration displacement.