Metal nanoparticle composites and manufacturing methods thereof by ultrasonic casting

A method of fabricating a metal-nanoparticle composite, the method comprising

• preparing a cavity inside a block of a metal;
• disposing nanoparticles in the cavity to provide a nanoparticle-metal block;
• melting the nanoparticle-metal block to provide a molten material;
• stirring the molten material to provide a stirred melt;
• ultrasonically treating the stirred melt to provide an ultrasonically-treated melt;
• and
• cooling the ultrasonically-treated melt to provide the metal-nanoparticle composite,
• the nanoparticles being boron nitride nanotubes (BNNTs), and the BNNTs in the metal-nanoparticle composite having an aspect ratio in a range of from 10,000 to 30,000.

A method of fabricating a metal-nanoparticle composite, the method comprising:

• preparing a cavity inside a block of a metal;
• disposing nanoparticles in the cavity to provide a nanoparticle-metal block;
• melting the nanoparticle-metal block to provide a molten material;
• stirring the molten material to provide a stirred melt;
• ultrasonically treating the stirred melt to provide an ultrasonically-treated melt;
• and
• cooling the ultrasonically-treated melt to provide the metal-nanoparticle composite,
• the nanoparticles being boron nitride nanotubes (BNNTs),
• the metal being aluminum (Al) or an Al alloy,
• the ultrasonically treating of the stirred melt comprising inserting a probe in the stirred melt to ultrasonically treat the stirred melt at a controlled amplitude and a controlled frequency for a predetermined period of time,
• the controlled amplitude being in a range of from 10 micrometers (μm) to 30 μm, the period of time being in a range of from 10 seconds (s) to 120 s, and the controlled frequency being in a range of from 18 kilohertz (kHz) to 20 kHz,
• a tip of the probe configured to be inserted in the stirred melt having a length in a range of from 4 millimeters (mm) to 8 mm,
• the melting of the nanoparticle-metal block comprising melting the nanoparticle-metal block in a crucible placed in a furnace at a predetermined temperature in a range of from 660° C. to 750° C.,
• the nanoparticles being pure nanoparticles that have not undergone any chemical pre-treatment or mechanical pre-treatment prior to being disposed in the cavity,
• the cavity having a diameter in a range of from 20 mm to 30 mm and a height in a range of from 15 mm to 20 mm,
• the nanoparticles being disposed in the cavity such that a volume percentage of the nanoparticles in the nanoparticle-metal block is in a range of from 0.5% to 5%,
• the BNNTs in the metal-nanoparticle composite having an aspect ratio in a range of from 10,000 to 30,000, and
• the BNNTs being uniformly dispersed within the metal in the metal-nanoparticle composite.